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受欢迎的三角函数 >

arctan(0.2x)+arctan(0.0625x)=54

解答

arctan (0.2 x) + arctan (0.0625 x) = 5 4^{\circ}

解答

x = \frac{65.45104 \dots - 5.25}{0.68819 \dots}

求解步骤

arctan (0.2 x) + arctan (0.0625 x) = 5 4^{\circ}

使用三角恒等式改写

arctan (0.2 x) + arctan (0.0625 x)

使用和差化积恒等式:

arctan (s) + arctan (t) = arctan (\frac{s + t}{1 - s t})

= arctan (\frac{0.2 x + 0.0625 x}{1 - 0.2 x \cdot 0.0625 x})

arctan (\frac{0.2 x + 0.0625 x}{1 - 0.2 x \cdot 0.0625 x}) = 5 4^{\circ}

使用反三角函数性质

arctan (\frac{0.2 x + 0.0625 x}{1 - 0.2 x \cdot 0.0625 x}) = 5 4^{\circ}

arctan (x) = a \Rightarrow x = tan (a)

\frac{0.2 x + 0.0625 x}{1 - 0.2 x \cdot 0.0625 x} = tan (5 4^{\circ})

tan (5 4^{\circ}) = \frac{( 3 10 + 5 2 ) 5 - 5}{20}

tan (5 4^{\circ})

使用三角恒等式改写:

\frac{sin ( 5 4 ^{\circ} )}{cos ( 5 4 ^{\circ} )}

tan (5 4^{\circ})

使用基本三角恒等式:

tan (x) = \frac{sin ( x )}{cos ( x )}

= \frac{sin ( 5 4 ^{\circ} )}{cos ( 5 4 ^{\circ} )}

= \frac{sin ( 5 4 ^{\circ} )}{cos ( 5 4 ^{\circ} )}

使用三角恒等式改写:

sin (5 4^{\circ}) = \frac{5 + 1}{4}

sin (5 4^{\circ})

使用三角恒等式改写:

cos (3 6^{\circ})

sin (5 4^{\circ})

利用以下特性:

sin (x) = cos (9 0^{\circ} - x)

= cos (9 0^{\circ} - 5 4^{\circ})

化简:

9 0^{\circ} - 5 4^{\circ} = 3 6^{\circ}

9 0^{\circ} - 5 4^{\circ}

2, 10

的最小公倍数:

10

2, 10

最小公倍数 (LCM)

2

质因数分解:

2

2

2

是质数，因此无法因数分解

= 2

10

质因数分解:

2 \cdot 5

10

10

除以

210 = 5 \cdot 2

= 2 \cdot 5

2, 5

都是质数，因此无法进一步因数分解

= 2 \cdot 5

将每个因子乘以它在

2

或

10

中出现的最多次数

= 2 \cdot 5

数字相乘:

2 \cdot 5 = 10

= 10

根据最小公倍数调整分式

将每个分子乘以其分母转变为最小公倍数所要乘以的同一数值

10

对于

9 0^{\circ} :

将分母和分子乘以

5

9 0^{\circ} = \frac{18 0 ^{\circ} 5}{2 \cdot 5} = 9 0^{\circ}

= 9 0^{\circ} - 5 4^{\circ}

因为分母相等，所以合并分式:

\frac{a}{c} \pm \frac{b}{c} = \frac{a \pm b}{c}

= \frac{18 0 ^{\circ} 5 - 54 0 ^{\circ}}{10}

同类项相加:

90 0^{\circ} - 54 0^{\circ} = 36 0^{\circ}

= 3 6^{\circ}

约分:

2

= 3 6^{\circ}

= cos (3 6^{\circ})

= cos (3 6^{\circ})

使用三角恒等式改写:

\frac{5 + 1}{4}

cos (3 6^{\circ})

显示:

cos (3 6^{\circ}) - sin (1 8^{\circ}) = \frac{1}{2}

使用以下积化和差公式:

2 sin (x) cos (y) = sin (x + y) - sin (x - y)

2 cos (3 6^{\circ}) sin (1 8^{\circ}) = sin (5 4^{\circ}) - sin (1 8^{\circ})

显示:

2 cos (3 6^{\circ}) sin (1 8^{\circ}) = \frac{1}{2}

使用倍角公式:

sin (2 x) = 2 sin (x) cos (x)

sin (7 2^{\circ}) = 2 sin (3 6^{\circ}) cos (3 6^{\circ})

sin (7 2^{\circ}) sin (3 6^{\circ}) = 4 sin (3 6^{\circ}) sin (1 8^{\circ}) cos (3 6^{\circ}) cos (1 8^{\circ})

两边除以

sin (3 6^{\circ})

sin (7 2^{\circ}) = 4 sin (1 8^{\circ}) cos (3 6^{\circ}) cos (1 8^{\circ})

利用以下特性:

sin (x) = cos (9 0^{\circ} - x)

sin (7 2^{\circ}) = cos (9 0^{\circ} - 7 2^{\circ})

cos (9 0^{\circ} - 7 2^{\circ}) = 4 sin (1 8^{\circ}) cos (3 6^{\circ}) cos (1 8^{\circ})

cos (1 8^{\circ}) = 4 sin (1 8^{\circ}) cos (3 6^{\circ}) cos (1 8^{\circ})

两边除以

cos (1 8^{\circ})

1 = 4 sin (1 8^{\circ}) cos (3 6^{\circ})

两边除以

2

\frac{1}{2} = 2 sin (1 8^{\circ}) cos (3 6^{\circ})

代入

\frac{1}{2} = 2 sin (1 8^{\circ}) cos (3 6^{\circ})

\frac{1}{2} = sin (5 4^{\circ}) - sin (1 8^{\circ})

sin (5 4^{\circ}) = cos (9 0^{\circ} - 5 4^{\circ})

\frac{1}{2} = cos (9 0^{\circ} - 5 4^{\circ}) - sin (1 8^{\circ})

\frac{1}{2} = cos (3 6^{\circ}) - sin (1 8^{\circ})

显示:

cos (3 6^{\circ}) + sin (1 8^{\circ}) = \frac{5}{4}

使用因式分解法则:

a^{2} - b^{2} = (a + b) (a - b)

a = cos (3 6^{\circ}) + sin (1 8^{\circ})

(cos (3 6^{\circ}) + sin (1 8^{\circ}))^{2} - (cos (3 6^{\circ}) - sin (1 8^{\circ}))^{2} = ((cos (3 6^{\circ}) + sin (1 8^{\circ})) + (cos (3 6^{\circ}) - sin (1 8^{\circ}))) ((cos (3 6^{\circ}) + sin (1 8^{\circ})) - (cos (3 6^{\circ}) - sin (1 8^{\circ})))

整理后得

(cos (3 6^{\circ}) + sin (1 8^{\circ}))^{2} - (cos (3 6^{\circ}) - sin (1 8^{\circ}))^{2} = 2 (2 cos (3 6^{\circ}) sin (1 8^{\circ}))

显示:

2 cos (3 6^{\circ}) sin (1 8^{\circ}) = \frac{1}{2}

使用倍角公式:

sin (2 x) = 2 sin (x) cos (x)

sin (7 2^{\circ}) = 2 sin (3 6^{\circ}) cos (3 6^{\circ})

sin (7 2^{\circ}) sin (3 6^{\circ}) = 4 sin (3 6^{\circ}) sin (1 8^{\circ}) cos (3 6^{\circ}) cos (1 8^{\circ})

两边除以

sin (3 6^{\circ})

sin (7 2^{\circ}) = 4 sin (1 8^{\circ}) cos (3 6^{\circ}) cos (1 8^{\circ})

利用以下特性:

sin (x) = cos (9 0^{\circ} - x)

sin (7 2^{\circ}) = cos (9 0^{\circ} - 7 2^{\circ})

cos (9 0^{\circ} - 7 2^{\circ}) = 4 sin (1 8^{\circ}) cos (3 6^{\circ}) cos (1 8^{\circ})

cos (1 8^{\circ}) = 4 sin (1 8^{\circ}) cos (3 6^{\circ}) cos (1 8^{\circ})

两边除以

cos (1 8^{\circ})

1 = 4 sin (1 8^{\circ}) cos (3 6^{\circ})

两边除以

2

\frac{1}{2} = 2 sin (1 8^{\circ}) cos (3 6^{\circ})

代入

2 cos (3 6^{\circ}) sin (1 8^{\circ}) = \frac{1}{2}

(cos (3 6^{\circ}) + sin (1 8^{\circ}))^{2} - (cos (3 6^{\circ}) - sin (1 8^{\circ}))^{2} = 1

代入

cos (3 6^{\circ}) - sin (1 8^{\circ}) = \frac{1}{2}

(cos (3 6^{\circ}) + sin (1 8^{\circ}))^{2} - (\frac{1}{2})^{2} = 1

整理后得

(cos (3 6^{\circ}) + sin (1 8^{\circ}))^{2} - \frac{1}{4} = 1

两边加上

\frac{1}{4}

(cos (3 6^{\circ}) + sin (1 8^{\circ}))^{2} - \frac{1}{4} + \frac{1}{4} = 1 + \frac{1}{4}

整理后得

(cos (3 6^{\circ}) + sin (1 8^{\circ}))^{2} = \frac{5}{4}

在两侧开平方

cos (3 6^{\circ}) + sin (1 8^{\circ}) = \pm \frac{5}{4}

cos (3 6^{\circ})

不能为负

sin (1 8^{\circ})

不能为负

cos (3 6^{\circ}) + sin (1 8^{\circ}) = \frac{5}{4}

以下方程式相加

cos (3 6^{\circ}) + sin (1 8^{\circ}) = \frac{5}{2}

((cos (3 6^{\circ}) + sin (1 8^{\circ})) + (cos (3 6^{\circ}) - sin (1 8^{\circ}))) = (\frac{5}{2} + \frac{1}{2})

整理后得

cos (3 6^{\circ}) = \frac{5 + 1}{4}

= \frac{5 + 1}{4}

= \frac{5 + 1}{4}

使用三角恒等式改写:

cos (5 4^{\circ}) = \frac{2 5 - 5}{4}

cos (5 4^{\circ})

使用三角恒等式改写:

sin (3 6^{\circ})

cos (5 4^{\circ})

利用以下特性:

cos (x) = sin (9 0^{\circ} - x)

= sin (9 0^{\circ} - 5 4^{\circ})

化简:

9 0^{\circ} - 5 4^{\circ} = 3 6^{\circ}

9 0^{\circ} - 5 4^{\circ}

2, 10

的最小公倍数:

10

2, 10

最小公倍数 (LCM)

2

质因数分解:

2

2

2

是质数，因此无法因数分解

= 2

10

质因数分解:

2 \cdot 5

10

10

除以

210 = 5 \cdot 2

= 2 \cdot 5

2, 5

都是质数，因此无法进一步因数分解

= 2 \cdot 5

将每个因子乘以它在

2

或

10

中出现的最多次数

= 2 \cdot 5

数字相乘:

2 \cdot 5 = 10

= 10

根据最小公倍数调整分式

将每个分子乘以其分母转变为最小公倍数所要乘以的同一数值

10

对于

9 0^{\circ} :

将分母和分子乘以

5

9 0^{\circ} = \frac{18 0 ^{\circ} 5}{2 \cdot 5} = 9 0^{\circ}

= 9 0^{\circ} - 5 4^{\circ}

因为分母相等，所以合并分式:

\frac{a}{c} \pm \frac{b}{c} = \frac{a \pm b}{c}

= \frac{18 0 ^{\circ} 5 - 54 0 ^{\circ}}{10}

同类项相加:

90 0^{\circ} - 54 0^{\circ} = 36 0^{\circ}

= 3 6^{\circ}

约分:

2

= 3 6^{\circ}

= sin (3 6^{\circ})

= sin (3 6^{\circ})

使用三角恒等式改写:

\frac{2 5 - 5}{4}

sin (3 6^{\circ})

显示:

cos (3 6^{\circ}) - sin (1 8^{\circ}) = \frac{1}{2}

使用以下积化和差公式:

2 sin (x) cos (y) = sin (x + y) - sin (x - y)

2 cos (3 6^{\circ}) sin (1 8^{\circ}) = sin (5 4^{\circ}) - sin (1 8^{\circ})

显示:

2 cos (3 6^{\circ}) sin (1 8^{\circ}) = \frac{1}{2}

使用倍角公式:

sin (2 x) = 2 sin (x) cos (x)

sin (7 2^{\circ}) = 2 sin (3 6^{\circ}) cos (3 6^{\circ})

sin (7 2^{\circ}) sin (3 6^{\circ}) = 4 sin (3 6^{\circ}) sin (1 8^{\circ}) cos (3 6^{\circ}) cos (1 8^{\circ})

两边除以

sin (3 6^{\circ})

sin (7 2^{\circ}) = 4 sin (1 8^{\circ}) cos (3 6^{\circ}) cos (1 8^{\circ})

利用以下特性:

sin (x) = cos (9 0^{\circ} - x)

sin (7 2^{\circ}) = cos (9 0^{\circ} - 7 2^{\circ})

cos (9 0^{\circ} - 7 2^{\circ}) = 4 sin (1 8^{\circ}) cos (3 6^{\circ}) cos (1 8^{\circ})

cos (1 8^{\circ}) = 4 sin (1 8^{\circ}) cos (3 6^{\circ}) cos (1 8^{\circ})

两边除以

cos (1 8^{\circ})

1 = 4 sin (1 8^{\circ}) cos (3 6^{\circ})

两边除以

2

\frac{1}{2} = 2 sin (1 8^{\circ}) cos (3 6^{\circ})

代入

\frac{1}{2} = 2 sin (1 8^{\circ}) cos (3 6^{\circ})

\frac{1}{2} = sin (5 4^{\circ}) - sin (1 8^{\circ})

sin (5 4^{\circ}) = cos (9 0^{\circ} - 5 4^{\circ})

\frac{1}{2} = cos (9 0^{\circ} - 5 4^{\circ}) - sin (1 8^{\circ})

\frac{1}{2} = cos (3 6^{\circ}) - sin (1 8^{\circ})

显示:

cos (3 6^{\circ}) + sin (1 8^{\circ}) = \frac{5}{4}

使用因式分解法则:

a^{2} - b^{2} = (a + b) (a - b)

a = cos (3 6^{\circ}) + sin (1 8^{\circ})

(cos (3 6^{\circ}) + sin (1 8^{\circ}))^{2} - (cos (3 6^{\circ}) - sin (1 8^{\circ}))^{2} = ((cos (3 6^{\circ}) + sin (1 8^{\circ})) + (cos (3 6^{\circ}) - sin (1 8^{\circ}))) ((cos (3 6^{\circ}) + sin (1 8^{\circ})) - (cos (3 6^{\circ}) - sin (1 8^{\circ})))

整理后得

(cos (3 6^{\circ}) + sin (1 8^{\circ}))^{2} - (cos (3 6^{\circ}) - sin (1 8^{\circ}))^{2} = 2 (2 cos (3 6^{\circ}) sin (1 8^{\circ}))

显示:

2 cos (3 6^{\circ}) sin (1 8^{\circ}) = \frac{1}{2}

使用倍角公式:

sin (2 x) = 2 sin (x) cos (x)

sin (7 2^{\circ}) = 2 sin (3 6^{\circ}) cos (3 6^{\circ})

sin (7 2^{\circ}) sin (3 6^{\circ}) = 4 sin (3 6^{\circ}) sin (1 8^{\circ}) cos (3 6^{\circ}) cos (1 8^{\circ})

两边除以

sin (3 6^{\circ})

sin (7 2^{\circ}) = 4 sin (1 8^{\circ}) cos (3 6^{\circ}) cos (1 8^{\circ})

利用以下特性:

sin (x) = cos (9 0^{\circ} - x)

sin (7 2^{\circ}) = cos (9 0^{\circ} - 7 2^{\circ})

cos (9 0^{\circ} - 7 2^{\circ}) = 4 sin (1 8^{\circ}) cos (3 6^{\circ}) cos (1 8^{\circ})

cos (1 8^{\circ}) = 4 sin (1 8^{\circ}) cos (3 6^{\circ}) cos (1 8^{\circ})

两边除以

cos (1 8^{\circ})

1 = 4 sin (1 8^{\circ}) cos (3 6^{\circ})

两边除以

2

\frac{1}{2} = 2 sin (1 8^{\circ}) cos (3 6^{\circ})

代入

2 cos (3 6^{\circ}) sin (1 8^{\circ}) = \frac{1}{2}

(cos (3 6^{\circ}) + sin (1 8^{\circ}))^{2} - (cos (3 6^{\circ}) - sin (1 8^{\circ}))^{2} = 1

代入

cos (3 6^{\circ}) - sin (1 8^{\circ}) = \frac{1}{2}

(cos (3 6^{\circ}) + sin (1 8^{\circ}))^{2} - (\frac{1}{2})^{2} = 1

整理后得

(cos (3 6^{\circ}) + sin (1 8^{\circ}))^{2} - \frac{1}{4} = 1

两边加上

\frac{1}{4}

(cos (3 6^{\circ}) + sin (1 8^{\circ}))^{2} - \frac{1}{4} + \frac{1}{4} = 1 + \frac{1}{4}

整理后得

(cos (3 6^{\circ}) + sin (1 8^{\circ}))^{2} = \frac{5}{4}

在两侧开平方

cos (3 6^{\circ}) + sin (1 8^{\circ}) = \pm \frac{5}{4}

cos (3 6^{\circ})

不能为负

sin (1 8^{\circ})

不能为负

cos (3 6^{\circ}) + sin (1 8^{\circ}) = \frac{5}{4}

以下方程式相加

cos (3 6^{\circ}) + sin (1 8^{\circ}) = \frac{5}{2}

((cos (3 6^{\circ}) + sin (1 8^{\circ})) + (cos (3 6^{\circ}) - sin (1 8^{\circ}))) = (\frac{5}{2} + \frac{1}{2})

整理后得

cos (3 6^{\circ}) = \frac{5 + 1}{4}

两边进行平方

(cos (3 6^{\circ}))^{2} = (\frac{5 + 1}{4})^{2}

利用以下特性:

sin^{2} (x) = 1 - cos^{2} (x)

sin^{2} (3 6^{\circ}) = 1 - cos^{2} (3 6^{\circ})

代入

cos (3 6^{\circ}) = \frac{5 + 1}{4}

sin^{2} (3 6^{\circ}) = 1 - (\frac{5 + 1}{4})^{2}

整理后得

sin^{2} (3 6^{\circ}) = \frac{5 - 5}{8}

在两侧开平方

sin (3 6^{\circ}) = \pm \frac{5 - 5}{8}

sin (3 6^{\circ})

不能为负

sin (3 6^{\circ}) = \frac{5 - 5}{8}

整理后得

sin (3 6^{\circ}) = \frac{\frac{5 - 5}{2}}{2}

= \frac{\frac{5 - 5}{2}}{2}

\frac{\frac{5 - 5}{2}}{2} = \frac{2 5 - 5}{4}

\frac{\frac{5 - 5}{2}}{2}

\frac{5 - 5}{2} = \frac{5 - 5}{2}

\frac{5 - 5}{2}

使用根式运算法则:

n \frac{a}{b} = \frac{n a}{n b},

假定

a \geq 0, b \geq 0

= \frac{5 - 5}{2}

= \frac{\frac{5 - 5}{2}}{2}

使用分式法则:

\frac{\frac{b}{c}}{a} = \frac{b}{c \cdot a}

= \frac{5 - 5}{2 \cdot 2}

\frac{5 - 5}{2 2}

有理化:

\frac{2 5 - 5}{4}

\frac{5 - 5}{2 2}

乘以共轭根式

\frac{2}{2}

= \frac{5 - 5 2}{2 \cdot 2 2}

2 \cdot 22 = 4

2 \cdot 22

使用指数法则:

a^{b} \cdot a^{c} = a^{b + c}

222 = 2 \cdot 2^{\frac{1}{2}} \cdot 2^{\frac{1}{2}} = 2^{1 + \frac{1}{2} + \frac{1}{2}}

= 2^{1 + \frac{1}{2} + \frac{1}{2}}

同类项相加:

\frac{1}{2} + \frac{1}{2} = 2 \cdot \frac{1}{2}

= 2^{1 + 2 \cdot \frac{1}{2}}

2 \cdot \frac{1}{2} = 1

2 \cdot \frac{1}{2}

分式相乘:

a \cdot \frac{b}{c} = \frac{a \cdot b}{c}

= \frac{1 \cdot 2}{2}

约分:

2

= 1

= 2^{1 + 1}

数字相加:

1 + 1 = 2

= 2^{2}

2^{2} = 4

= 4

= \frac{2 5 - 5}{4}

= \frac{2 5 - 5}{4}

= \frac{2 5 - 5}{4}

= \frac{2 5 - 5}{4}

= \frac{\frac{5 + 1}{4}}{\frac{2 5 - 5}{4}}

化简

\frac{\frac{5 + 1}{4}}{\frac{2 5 - 5}{4}} : \frac{( 3 10 + 5 2 ) 5 - 5}{20}

\frac{\frac{5 + 1}{4}}{\frac{2 5 - 5}{4}}

分式相除:

\frac{\frac{a}{b}}{\frac{c}{d}} = \frac{a \cdot d}{b \cdot c}

= \frac{( 5 + 1 ) \cdot 4}{4 2 5 - 5}

约分:

4

= \frac{5 + 1}{2 5 - 5}

\frac{5 + 1}{2 5 - 5}

有理化:

\frac{( 3 10 + 5 2 ) 5 - 5}{20}

\frac{5 + 1}{2 5 - 5}

乘以共轭根式

\frac{2}{2}

= \frac{( 5 + 1 ) 2}{2 5 - 5 2}

2 5 - 5 2 = 2 5 - 5

2 5 - 5 2

使用根式运算法则:

a a = a

22 = 2

= 2 5 - 5

= \frac{2 ( 5 + 1 )}{2 5 - 5}

乘以共轭根式

\frac{5 - 5}{5 - 5}

= \frac{2 ( 5 + 1 ) 5 - 5}{2 5 - 5 5 - 5}

2 5 - 5 5 - 5 = 10 - 25

2 5 - 5 5 - 5

使用根式运算法则:

a a = a

5 - 5 5 - 5 = 5 - 5

= 2 (5 - 5)

使用分配律:

a (b - c) = ab - a c

a = 2, b = 5, c = 5

= 2 \cdot 5 - 25

数字相乘:

2 \cdot 5 = 10

= 10 - 25

= \frac{2 ( 5 + 1 ) 5 - 5}{10 - 2 5}

因式分解出通项

- 2 : - 2 (5 - 5)

- 25 + 10

将

10

改写为

2 \cdot 5

= - 25 + 2 \cdot 5

因式分解出通项

- 2

= - 2 (5 - 5)

= - \frac{2 ( 5 + 1 ) 5 - 5}{2 ( 5 - 5 )}

消掉

- \frac{2 ( 5 + 1 ) 5 - 5}{2 ( 5 - 5 )} : \frac{2 ( 5 + 1 ) 5 - 5}{2 ( 5 - 5 )}

- \frac{2 ( 5 + 1 ) 5 - 5}{2 ( 5 - 5 )}

5 - 5 = - (5 - 5)

= - \frac{2 ( 1 + 5 ) 5 - 5}{- 2 ( 5 - 5 )}

整理后得

= \frac{2 ( 5 + 1 ) 5 - 5}{2 ( 5 - 5 )}

= \frac{2 ( 5 + 1 ) 5 - 5}{2 ( 5 - 5 )}

乘以共轭根式

\frac{5 + 5}{5 + 5}

= \frac{2 ( 5 + 1 ) 5 - 5 ( 5 + 5 )}{2 ( 5 - 5 ) ( 5 + 5 )}

2 (5 + 1) 5 - 5 (5 + 5) = 610 5 - 5 + 102 5 - 5

2 (5 + 1) 5 - 5 (5 + 5)

= 2 (5 + 1) (5 + 5) 5 - 5

乘开

(5 + 1) (5 + 5) : 65 + 10

(5 + 1) (5 + 5)

使用 FOIL 方法:

(a + b) (c + d) = a c + a d + b c + b d

a = 5, b = 1, c = 5, d = 5

= 5 \cdot 5 + 55 + 1 \cdot 5 + 1 \cdot 5

= 55 + 55 + 1 \cdot 5 + 1 \cdot 5

化简

55 + 55 + 1 \cdot 5 + 1 \cdot 5 : 65 + 10

55 + 55 + 1 \cdot 5 + 1 \cdot 5

同类项相加:

55 + 1 \cdot 5 = 65

= 65 + 55 + 1 \cdot 5

使用根式运算法则:

a a = a

55 = 5

= 65 + 5 + 1 \cdot 5

数字相乘:

1 \cdot 5 = 5

= 65 + 5 + 5

数字相加:

5 + 5 = 10

= 65 + 10

= 65 + 10

= 2 5 - 5 (65 + 10)

乘开

2 5 - 5 (65 + 10) : 610 5 - 5 + 102 5 - 5

2 5 - 5 (65 + 10)

使用分配律:

a (b + c) = ab + a c

a = 2 5 - 5, b = 65, c = 10

= 2 5 - 5 \cdot 65 + 2 5 - 5 \cdot 10

= 625 5 - 5 + 102 5 - 5

625 5 - 5 = 610 5 - 5

625 5 - 5

使用根式运算法则:

a b = a \cdot b

25 5 - 5 = 2 \cdot 5 (5 - 5)

= 6 2 \cdot 5 (5 - 5)

数字相乘:

2 \cdot 5 = 10

= 6 10 (5 - 5)

使用根式运算法则:

n ab = n a n b,

假定

a \geq 0, b \geq 0

10 (5 - 5) = 10 5 - 5

= 610 5 - 5

= 610 5 - 5 + 102 5 - 5

= 610 5 - 5 + 102 5 - 5

2 (5 - 5) (5 + 5) = 40

2 (5 - 5) (5 + 5)

乘开

(5 - 5) (5 + 5) : 20

(5 - 5) (5 + 5)

使用平方差公式:

(a - b) (a + b) = a^{2} - b^{2}

a = 5, b = 5

= 5^{2} - (5)^{2}

化简

5^{2} - (5)^{2} : 20

5^{2} - (5)^{2}

5^{2} = 25

5^{2}

5^{2} = 25

= 25

(5)^{2} = 5

(5)^{2}

使用根式运算法则:

a = a^{\frac{1}{2}}

= (5^{\frac{1}{2}})^{2}

使用指数法则:

(a^{b})^{c} = a^{b c}

= 5^{\frac{1}{2} \cdot 2}

\frac{1}{2} \cdot 2 = 1

\frac{1}{2} \cdot 2

分式相乘:

a \cdot \frac{b}{c} = \frac{a \cdot b}{c}

= \frac{1 \cdot 2}{2}

约分:

2

= 1

= 5

= 25 - 5

数字相减:

25 - 5 = 20

= 20

= 20

= 2 \cdot 20

乘开

2 \cdot 20 : 40

2 \cdot 20

打开括号

= 2 \cdot 20

数字相乘:

2 \cdot 20 = 40

= 40

= 40

= \frac{6 10 5 - 5 + 10 2 5 - 5}{40}

分解

610 5 - 5 + 102 5 - 5 : 2 5 - 5 (310 + 52)

610 5 - 5 + 102 5 - 5

改写为

= 3 \cdot 2 5 - 5 10 + 5 \cdot 2 5 - 5 2

因式分解出通项

2 5 - 5

= 2 5 - 5 (310 + 52)

= \frac{2 5 - 5 ( 3 10 + 5 2 )}{40}

约分:

2

= \frac{( 3 10 + 5 2 ) 5 - 5}{20}

= \frac{( 3 10 + 5 2 ) 5 - 5}{20}

= \frac{( 3 10 + 5 2 ) 5 - 5}{20}

\frac{0.2 x + 0.0625 x}{1 - 0.2 x \cdot 0.0625 x} = \frac{( 3 10 + 5 2 ) 5 - 5}{20}

\frac{0.2 x + 0.0625 x}{1 - 0.2 x \cdot 0.0625 x} = \frac{( 3 10 + 5 2 ) 5 - 5}{20}

解

\frac{0.2 x + 0.0625 x}{1 - 0.2 x \cdot 0.0625 x} = \frac{( 3 10 + 5 2 ) 5 - 5}{20} : x = - \frac{5.25 + 65.45104 \dots}{0.68819 \dots}, x = \frac{65.45104 \dots - 5.25}{0.68819 \dots}

\frac{0.2 x + 0.0625 x}{1 - 0.2 x \cdot 0.0625 x} = \frac{( 3 10 + 5 2 ) 5 - 5}{20}

使用分式交叉相乘

\frac{0.2 x + 0.0625 x}{1 - 0.2 x \cdot 0.0625 x} = \frac{( 3 10 + 5 2 ) 5 - 5}{20}

化简

\frac{0.2 x + 0.0625 x}{1 - 0.2 x \cdot 0.0625 x} : \frac{0.2625 x}{1 - 0.0125 x ^{2}}

\frac{0.2 x + 0.0625 x}{1 - 0.2 x \cdot 0.0625 x}

同类项相加:

0.2 x + 0.0625 x = 0.2625 x

= \frac{0.2625 x}{1 - 0.2 x \cdot 0.0625 x}

化简

0.2 x \cdot 0.0625 x : 0.0125 x^{2}

0.2 x \cdot 0.0625 x

数字相乘:

0.2 \cdot 0.0625 = 0.0125

= 0.0125 xx

使用指数法则:

aa = a^{2}

xx = x^{2}

= 0.0125 x^{2}

= \frac{0.2625 x}{1 - 0.0125 x ^{2}}

\frac{0.2625 x}{1 - 0.0125 x ^{2}} = \frac{( 3 10 + 5 2 ) 5 - 5}{20}

使用分式交叉相乘: 若

\frac{a}{b} = \frac{c}{d}

则

a \cdot d = b \cdot c

0.2625 x \cdot 20 = (1 - 0.0125 x^{2}) (310 + 52) 5 - 5

化简

0.2625 x \cdot 20 : 5.25 x

0.2625 x \cdot 20

数字相乘:

0.2625 \cdot 20 = 5.25

= 5.25 x

5.25 x = (1 - 0.0125 x^{2}) (310 + 52) 5 - 5

5.25 x = (1 - 0.0125 x^{2}) (310 + 52) 5 - 5

解

5.25 x = (1 - 0.0125 x^{2}) (310 + 52) 5 - 5 : x = - \frac{5.25 + 65.45104 \dots}{0.68819 \dots}, x = \frac{65.45104 \dots - 5.25}{0.68819 \dots}

5.25 x = (1 - 0.0125 x^{2}) (310 + 52) 5 - 5

展开

(1 - 0.0125 x^{2}) (310 + 52) 5 - 5 : 3 50 - 105 + 5 10 - 25 - 0.0375 50 - 105 x^{2} - 0.0625 10 - 25 x^{2}

(1 - 0.0125 x^{2}) (310 + 52) 5 - 5

= (310 + 52) 5 - 5 (1 - 0.0125 x^{2})

乘开

(1 - 0.0125 x^{2}) (310 + 52) : 310 + 52 - 10 \cdot 0.0375 x^{2} - 2 \cdot 0.0625 x^{2}

(1 - 0.0125 x^{2}) (310 + 52)

使用 FOIL 方法:

(a + b) (c + d) = a c + a d + b c + b d

a = 1, b = - 0.0125 x^{2}, c = 310, d = 52

= 1 \cdot 310 + 1 \cdot 52 + (- 0.0125 x^{2}) \cdot 310 + (- 0.0125 x^{2}) \cdot 52

使用加减运算法则

+ (- a) = - a

= 1 \cdot 310 + 1 \cdot 52 - 310 \cdot 0.0125 x^{2} - 52 \cdot 0.0125 x^{2}

化简

1 \cdot 310 + 1 \cdot 52 - 310 \cdot 0.0125 x^{2} - 52 \cdot 0.0125 x^{2} : 310 + 52 - 10 \cdot 0.0375 x^{2} - 2 \cdot 0.0625 x^{2}

1 \cdot 310 + 1 \cdot 52 - 310 \cdot 0.0125 x^{2} - 52 \cdot 0.0125 x^{2}

1 \cdot 310 = 310

1 \cdot 310

数字相乘:

1 \cdot 3 = 3

= 310

1 \cdot 52 = 52

1 \cdot 52

数字相乘:

1 \cdot 5 = 5

= 52

310 \cdot 0.0125 x^{2} = 10 \cdot 0.0375 x^{2}

310 \cdot 0.0125 x^{2}

数字相乘:

3 \cdot 0.0125 = 0.0375

= 10 \cdot 0.0375 x^{2}

52 \cdot 0.0125 x^{2} = 2 \cdot 0.0625 x^{2}

52 \cdot 0.0125 x^{2}

数字相乘:

5 \cdot 0.0125 = 0.0625

= 2 \cdot 0.0625 x^{2}

= 310 + 52 - 10 \cdot 0.0375 x^{2} - 2 \cdot 0.0625 x^{2}

= 310 + 52 - 10 \cdot 0.0375 x^{2} - 2 \cdot 0.0625 x^{2}

= 5 - 5 (310 + 52 - 10 \cdot 0.0375 x^{2} - 2 \cdot 0.0625 x^{2})

乘开

5 - 5 (310 + 52 - 10 \cdot 0.0375 x^{2} - 2 \cdot 0.0625 x^{2}) : 3 50 - 105 + 5 10 - 25 - 0.0375 50 - 105 x^{2} - 0.0625 10 - 25 x^{2}

5 - 5 (310 + 52 - 10 \cdot 0.0375 x^{2} - 2 \cdot 0.0625 x^{2})

打开括号

= 5 - 5 \cdot 310 + 5 - 5 \cdot 52 + 5 - 5 (- 10 \cdot 0.0375 x^{2}) + 5 - 5 (- 2 \cdot 0.0625 x^{2})

使用加减运算法则

+ (- a) = - a

= 310 5 - 5 + 52 5 - 5 - 10 \cdot 0.0375 5 - 5 x^{2} - 2 \cdot 0.0625 5 - 5 x^{2}

化简

310 5 - 5 + 52 5 - 5 - 10 \cdot 0.0375 5 - 5 x^{2} - 2 \cdot 0.0625 5 - 5 x^{2} : 3 50 - 105 + 5 10 - 25 - 0.0375 50 - 105 x^{2} - 0.0625 10 - 25 x^{2}

310 5 - 5 + 52 5 - 5 - 10 \cdot 0.0375 5 - 5 x^{2} - 2 \cdot 0.0625 5 - 5 x^{2}

310 5 - 5 = 3 50 - 105

310 5 - 5

使用根式运算法则:

a b = a \cdot b

10 5 - 5 = 10 (5 - 5)

= 3 10 (5 - 5)

乘开

10 (5 - 5) : 50 - 105

10 (5 - 5)

使用分配律:

a (b - c) = ab - a c

a = 10, b = 5, c = 5

= 10 \cdot 5 - 105

数字相乘:

10 \cdot 5 = 50

= 50 - 105

= 3 50 - 105

52 5 - 5 = 5 10 - 25

52 5 - 5

使用根式运算法则:

a b = a \cdot b

2 5 - 5 = 2 (5 - 5)

= 5 2 (5 - 5)

乘开

2 (5 - 5) : 10 - 25

2 (5 - 5)

使用分配律:

a (b - c) = ab - a c

a = 2, b = 5, c = 5

= 2 \cdot 5 - 25

数字相乘:

2 \cdot 5 = 10

= 10 - 25

= 5 10 - 25

10 \cdot 0.0375 5 - 5 x^{2} = 0.0375 50 - 105 x^{2}

10 \cdot 0.0375 5 - 5 x^{2}

使用根式运算法则:

a b = a \cdot b

10 5 - 5 = 10 (5 - 5)

= 0.0375 10 (5 - 5) x^{2}

乘开

10 (5 - 5) : 50 - 105

10 (5 - 5)

使用分配律:

a (b - c) = ab - a c

a = 10, b = 5, c = 5

= 10 \cdot 5 - 105

数字相乘:

10 \cdot 5 = 50

= 50 - 105

= 0.0375 50 - 105 x^{2}

2 \cdot 0.0625 5 - 5 x^{2} = 0.0625 10 - 25 x^{2}

2 \cdot 0.0625 5 - 5 x^{2}

使用根式运算法则:

a b = a \cdot b

2 5 - 5 = 2 (5 - 5)

= 0.0625 2 (5 - 5) x^{2}

乘开

2 (5 - 5) : 10 - 25

2 (5 - 5)

使用分配律:

a (b - c) = ab - a c

a = 2, b = 5, c = 5

= 2 \cdot 5 - 25

数字相乘:

2 \cdot 5 = 10

= 10 - 25

= 0.0625 10 - 25 x^{2}

= 3 50 - 105 + 5 10 - 25 - 0.0375 50 - 105 x^{2} - 0.0625 10 - 25 x^{2}

= 3 50 - 105 + 5 10 - 25 - 0.0375 50 - 105 x^{2} - 0.0625 10 - 25 x^{2}

= 3 50 - 105 + 5 10 - 25 - 0.0375 50 - 105 x^{2} - 0.0625 10 - 25 x^{2}

5.25 x = 3 50 - 105 + 5 10 - 25 - 0.0375 50 - 105 x^{2} - 0.0625 10 - 25 x^{2}

交换两边

3 50 - 105 + 5 10 - 25 - 0.0375 50 - 105 x^{2} - 0.0625 10 - 25 x^{2} = 5.25 x

将

5.25 x

para o lado esquerdo

3 50 - 105 + 5 10 - 25 - 0.0375 50 - 105 x^{2} - 0.0625 10 - 25 x^{2} = 5.25 x

两边减去

5.25 x

3 50 - 105 + 5 10 - 25 - 0.0375 50 - 105 x^{2} - 0.0625 10 - 25 x^{2} - 5.25 x = 5.25 x - 5.25 x

化简

3 50 - 105 + 5 10 - 25 - 0.0375 50 - 105 x^{2} - 0.0625 10 - 25 x^{2} - 5.25 x = 0

3 50 - 105 + 5 10 - 25 - 0.0375 50 - 105 x^{2} - 0.0625 10 - 25 x^{2} - 5.25 x = 0

改写成标准形式

a x^{2} + b x + c = 0

- 0.34409 \dots x^{2} - 5.25 x + 27.52763 \dots = 0

使用求根公式求解

- 0.34409 \dots x^{2} - 5.25 x + 27.52763 \dots = 0

二次方程求根公式:

若

a = - 0.34409 \dots, b = - 5.25, c = 27.52763 \dots

x_{1, 2} = \frac{- ( - 5.25 ) \pm ( - 5.25 ) ^{2} - 4 ( - 0.34409 \dots ) \cdot 27.52763 \dots}{2 ( - 0.34409 \dots )}

x_{1, 2} = \frac{- ( - 5.25 ) \pm ( - 5.25 ) ^{2} - 4 ( - 0.34409 \dots ) \cdot 27.52763 \dots}{2 ( - 0.34409 \dots )}

(- 5.25)^{2} - 4 (- 0.34409 \dots) \cdot 27.52763 \dots = 65.45104 \dots

(- 5.25)^{2} - 4 (- 0.34409 \dots) \cdot 27.52763 \dots

使用法则

- (- a) = a

= (- 5.25)^{2} + 4 \cdot 0.34409 \dots \cdot 27.52763 \dots

使用指数法则:

(- a)^{n} = a^{n},

若

n

是偶数

(- 5.25)^{2} = 5.2 5^{2}

= 5.2 5^{2} + 4 \cdot 0.34409 \dots \cdot 27.52763 \dots

数字相乘:

4 \cdot 0.34409 \dots \cdot 27.52763 \dots = 37.88854 \dots

= 5.2 5^{2} + 37.88854 \dots

5.2 5^{2} = 27.5625

= 27.5625 + 37.88854 \dots

数字相加:

27.5625 + 37.88854 \dots = 65.45104 \dots

= 65.45104 \dots

x_{1, 2} = \frac{- ( - 5.25 ) \pm 65.45104 \dots}{2 ( - 0.34409 \dots )}

将解分隔开

x_{1} = \frac{- ( - 5.25 ) + 65.45104 \dots}{2 ( - 0.34409 \dots )}, x_{2} = \frac{- ( - 5.25 ) - 65.45104 \dots}{2 ( - 0.34409 \dots )}

x = \frac{- ( - 5.25 ) + 65.45104 \dots}{2 ( - 0.34409 \dots )} : - \frac{5.25 + 65.45104 \dots}{0.68819 \dots}

\frac{- ( - 5.25 ) + 65.45104 \dots}{2 ( - 0.34409 \dots )}

去除括号:

(- a) = - a, - (- a) = a

= \frac{5.25 + 65.45104 \dots}{- 2 \cdot 0.34409 \dots}

数字相乘:

2 \cdot 0.34409 \dots = 0.68819 \dots

= \frac{5.25 + 65.45104 \dots}{- 0.68819 \dots}

使用分式法则:

\frac{a}{- b} = - \frac{a}{b}

= - \frac{5.25 + 65.45104 \dots}{0.68819 \dots}

x = \frac{- ( - 5.25 ) - 65.45104 \dots}{2 ( - 0.34409 \dots )} : \frac{65.45104 \dots - 5.25}{0.68819 \dots}

\frac{- ( - 5.25 ) - 65.45104 \dots}{2 ( - 0.34409 \dots )}

去除括号:

(- a) = - a, - (- a) = a

= \frac{5.25 - 65.45104 \dots}{- 2 \cdot 0.34409 \dots}

数字相乘:

2 \cdot 0.34409 \dots = 0.68819 \dots

= \frac{5.25 - 65.45104 \dots}{- 0.68819 \dots}

使用分式法则:

\frac{- a}{- b} = \frac{a}{b}

5.25 - 65.45104 \dots = - (65.45104 \dots - 5.25)

= \frac{65.45104 \dots - 5.25}{0.68819 \dots}

二次方程组的解是:

x = - \frac{5.25 + 65.45104 \dots}{0.68819 \dots}, x = \frac{65.45104 \dots - 5.25}{0.68819 \dots}

x = - \frac{5.25 + 65.45104 \dots}{0.68819 \dots}, x = \frac{65.45104 \dots - 5.25}{0.68819 \dots}

验证解

找到无定义的点（奇点）:

x = 45, x = - 45

取

\frac{0.2 x + 0.0625 x}{1 - 0.2 x \cdot 0.0625 x}

的分母，令其等于零

解

1 - 0.2 x \cdot 0.0625 x = 0 : x = 45, x = - 45

1 - 0.2 x \cdot 0.0625 x = 0

将

1

到右边

1 - 0.2 x \cdot 0.0625 x = 0

两边减去

1

1 - 0.2 x \cdot 0.0625 x - 1 = 0 - 1

化简

- 0.2 x \cdot 0.0625 x = - 1

- 0.2 x \cdot 0.0625 x = - 1

化简

- 0.0125 x^{2} = - 1

两边除以

- 0.0125

\frac{- 0.0125 x ^{2}}{- 0.0125} = \frac{- 1}{- 0.0125}

x^{2} = \frac{1}{0.0125}

对于

x^{2} = f (a)

解为

x = f (a), - f (a)

x = \frac{1}{0.0125}, x = - \frac{1}{0.0125}

\frac{1}{0.0125} = 45

\frac{1}{0.0125}

使用根式运算法则:

\frac{a}{b} = \frac{a}{b}, a \geq 0, b \geq 0

= \frac{1}{0.0125}

使用根式运算法则:

1 = 1

1 = 1

= \frac{1}{0.0125}

0.0125 = \frac{1}{4 5}

0.0125

0.0125 = \frac{1}{80}

0.0125

小数点后有几位数字就乘以和除以几次 10。

小数点右侧有

4

位，因此乘以和除以

10000

= \frac{10000 \cdot 0.0125}{10000}

数字相乘:

10000 \cdot 0.0125 = 125

= \frac{125}{10000}

对数字约分

\frac{125}{10000} = \frac{1}{80}

= \frac{1}{80}

= \frac{1}{80}

使用根式运算法则:

\frac{a}{b} = \frac{a}{b}, a \geq 0, b \geq 0

= \frac{1}{80}

使用根式运算法则:

1 = 1

1 = 1

= \frac{1}{80}

80 = 45

80

80

质因数分解:

2^{4} \cdot 5

80

80

除以

280 = 40 \cdot 2

= 2 \cdot 40

40

除以

240 = 20 \cdot 2

= 2 \cdot 2 \cdot 20

20

除以

220 = 10 \cdot 2

= 2 \cdot 2 \cdot 2 \cdot 10

10

除以

210 = 5 \cdot 2

= 2 \cdot 2 \cdot 2 \cdot 2 \cdot 5

2, 5

都是质数，因此无法进一步因数分解

= 2 \cdot 2 \cdot 2 \cdot 2 \cdot 5

= 2^{4} \cdot 5

= 2^{4} \cdot 5

使用根式运算法则:

ab = a b, a \geq 0, b \geq 0

2^{4} \cdot 5 = 2^{4} 5

= 2^{4} 5

2^{4} = 4

2^{4}

使用根式运算法则:

n a^{m} = a^{\frac{m}{n}}, a \geq 0

2^{4} = 2^{\frac{4}{2}}

= 2^{\frac{4}{2}}

数字相除:

\frac{4}{2} = 2

= 2^{2}

2^{2} = 4

= 4

= 45

= \frac{1}{4 5}

= \frac{1}{\frac{1}{4 5}}

使用分式法则:

\frac{1}{\frac{b}{c}} = \frac{c}{b}

= \frac{4 5}{1}

使用分式法则:

\frac{a}{1} = a

= 45

- \frac{1}{0.0125} = - 45

- \frac{1}{0.0125}

使用根式运算法则:

\frac{a}{b} = \frac{a}{b}, a \geq 0, b \geq 0

= - \frac{1}{0.0125}

使用根式运算法则:

1 = 1

1 = 1

= - \frac{1}{0.0125}

0.0125 = \frac{1}{4 5}

0.0125

0.0125 = \frac{1}{80}

0.0125

小数点后有几位数字就乘以和除以几次 10。

小数点右侧有

4

位，因此乘以和除以

10000

= \frac{10000 \cdot 0.0125}{10000}

数字相乘:

10000 \cdot 0.0125 = 125

= \frac{125}{10000}

对数字约分

\frac{125}{10000} = \frac{1}{80}

= \frac{1}{80}

= \frac{1}{80}

使用根式运算法则:

\frac{a}{b} = \frac{a}{b}, a \geq 0, b \geq 0

= \frac{1}{80}

使用根式运算法则:

1 = 1

1 = 1

= \frac{1}{80}

80 = 45

80

80

质因数分解:

2^{4} \cdot 5

80

80

除以

280 = 40 \cdot 2

= 2 \cdot 40

40

除以

240 = 20 \cdot 2

= 2 \cdot 2 \cdot 20

20

除以

220 = 10 \cdot 2

= 2 \cdot 2 \cdot 2 \cdot 10

10

除以

210 = 5 \cdot 2

= 2 \cdot 2 \cdot 2 \cdot 2 \cdot 5

2, 5

都是质数，因此无法进一步因数分解

= 2 \cdot 2 \cdot 2 \cdot 2 \cdot 5

= 2^{4} \cdot 5

= 2^{4} \cdot 5

使用根式运算法则:

ab = a b, a \geq 0, b \geq 0

2^{4} \cdot 5 = 2^{4} 5

= 2^{4} 5

2^{4} = 4

2^{4}

使用根式运算法则:

n a^{m} = a^{\frac{m}{n}}, a \geq 0

2^{4} = 2^{\frac{4}{2}}

= 2^{\frac{4}{2}}

数字相除:

\frac{4}{2} = 2

= 2^{2}

2^{2} = 4

= 4

= 45

= \frac{1}{4 5}

= - \frac{1}{\frac{1}{4 5}}

使用分式法则:

\frac{1}{\frac{b}{c}} = \frac{c}{b}

\frac{1}{\frac{1}{4 5}} = \frac{4 5}{1}

= - \frac{4 5}{1}

使用分式法则:

\frac{a}{1} = a

= - 45

x = 45, x = - 45

以下点无定义

x = 45, x = - 45

将不在定义域的点与解相综合:

x = - \frac{5.25 + 65.45104 \dots}{0.68819 \dots}, x = \frac{65.45104 \dots - 5.25}{0.68819 \dots}

x = - \frac{5.25 + 65.45104 \dots}{0.68819 \dots}, x = \frac{65.45104 \dots - 5.25}{0.68819 \dots}

将解代入原方程进行验证

将它们代入

arctan (0.2 x) + arctan (0.0625 x) = 5 4^{\circ}

检验解是否符合

去除与方程不符的解。

检验

- \frac{5.25 + 65.45104 \dots}{0.68819 \dots}

的解:

假

- \frac{5.25 + 65.45104 \dots}{0.68819 \dots}

代入

n = 1

- \frac{5.25 + 65.45104 \dots}{0.68819 \dots}

对于

arctan (0.2 x) + arctan (0.0625 x) = 5 4^{\circ}

代入

x = - \frac{5.25 + 65.45104 \dots}{0.68819 \dots}

arctan (0.2 (- \frac{5.25 + 65.45104 \dots}{0.68819 \dots})) + arctan (0.0625 (- \frac{5.25 + 65.45104 \dots}{0.68819 \dots})) = 5 4^{\circ}

整理后得

- 2.19911 \dots = 0.94247 \dots

\Rightarrow 假

检验

\frac{65.45104 \dots - 5.25}{0.68819 \dots}

的解:

真

\frac{65.45104 \dots - 5.25}{0.68819 \dots}

代入

n = 1

\frac{65.45104 \dots - 5.25}{0.68819 \dots}

对于

arctan (0.2 x) + arctan (0.0625 x) = 5 4^{\circ}

代入

x = \frac{65.45104 \dots - 5.25}{0.68819 \dots}

arctan (0.2 \cdot \frac{65.45104 \dots - 5.25}{0.68819 \dots}) + arctan (0.0625 \cdot \frac{65.45104 \dots - 5.25}{0.68819 \dots}) = 5 4^{\circ}

整理后得

0.94247 \dots = 0.94247 \dots

\Rightarrow 真

x = \frac{65.45104 \dots - 5.25}{0.68819 \dots}

作图

流行的例子

sin^2(θ)+cos(θ)=1

sin^{2} (θ) + cos (θ) = 1

tan (x) = (\frac{3}{4})

cos (x) = - 0.6987

sin(3x)=(sqrt(2))/2 ,0<= x<= 2pi

sin (3 x) = \frac{2}{2}, 0 \leq x \leq 2 π

3sin(θ)=sin(θ)-sqrt(2)

3 sin (θ) = sin (θ) - 2