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受欢迎的三角函数 >

(cos(-30+x))/(cos(30+x))= 1835/726

解答

\frac{cos ( - 3 0 ^{\circ} + x )}{cos ( 3 0 ^{\circ} + x )} = \frac{1835}{726}

解答

x = 0.64352 \dots + 18 0^{\circ} n

+1

弧度

x = 0.64352 \dots + πn

求解步骤

\frac{cos ( - 3 0 ^{\circ} + x )}{cos ( 3 0 ^{\circ} + x )} = \frac{1835}{726}

使用三角恒等式改写

\frac{cos ( - 3 0 ^{\circ} + x )}{cos ( 3 0 ^{\circ} + x )} = \frac{1835}{726}

使用三角恒等式改写

cos (3 0^{\circ} + x)

使用角和恒等式:

cos (s + t) = cos (s) cos (t) - sin (s) sin (t)

= cos (3 0^{\circ}) cos (x) - sin (3 0^{\circ}) sin (x)

化简

cos (3 0^{\circ}) cos (x) - sin (3 0^{\circ}) sin (x) : \frac{3}{2} cos (x) - \frac{1}{2} sin (x)

cos (3 0^{\circ}) cos (x) - sin (3 0^{\circ}) sin (x)

化简

cos (3 0^{\circ}) : \frac{3}{2}

cos (3 0^{\circ})

使用以下普通恒等式:

cos (3 0^{\circ}) = \frac{3}{2}

cos (x)

周期表（周期为

36 0^{\circ} n

）：

x 0 3 0^{\circ} 4 5^{\circ} 6 0^{\circ} 9 0^{\circ} 12 0^{\circ} 13 5^{\circ} 15 0^{\circ} cos (x) 1 \frac{3}{2} \frac{2}{2} \frac{1}{2} 0 - \frac{1}{2} - \frac{2}{2} - \frac{3}{2} x 18 0^{\circ} 21 0^{\circ} 22 5^{\circ} 24 0^{\circ} 27 0^{\circ} 30 0^{\circ} 31 5^{\circ} 33 0^{\circ} cos (x) - 1 - \frac{3}{2} - \frac{2}{2} - \frac{1}{2} 0 \frac{1}{2} \frac{2}{2} \frac{3}{2}

= \frac{3}{2}

= \frac{3}{2} cos (x) - sin (3 0^{\circ}) sin (x)

化简

sin (3 0^{\circ}) : \frac{1}{2}

sin (3 0^{\circ})

使用以下普通恒等式:

sin (3 0^{\circ}) = \frac{1}{2}

sin (x)

周期表（周期为

36 0^{\circ} n

"）：

x 0 3 0^{\circ} 4 5^{\circ} 6 0^{\circ} 9 0^{\circ} 12 0^{\circ} 13 5^{\circ} 15 0^{\circ} sin (x) 0 \frac{1}{2} \frac{2}{2} \frac{3}{2} 1 \frac{3}{2} \frac{2}{2} \frac{1}{2} x 18 0^{\circ} 21 0^{\circ} 22 5^{\circ} 24 0^{\circ} 27 0^{\circ} 30 0^{\circ} 31 5^{\circ} 33 0^{\circ} sin (x) 0 - \frac{1}{2} - \frac{2}{2} - \frac{3}{2} - 1 - \frac{3}{2} - \frac{2}{2} - \frac{1}{2}

= \frac{1}{2}

= \frac{3}{2} cos (x) - \frac{1}{2} sin (x)

= \frac{3}{2} cos (x) - \frac{1}{2} sin (x)

使用角差恒等式:

cos (s - t) = cos (s) cos (t) + sin (s) sin (t)

= cos (x) cos (3 0^{\circ}) + sin (x) sin (3 0^{\circ})

化简

cos (x) cos (3 0^{\circ}) + sin (x) sin (3 0^{\circ}) : \frac{3}{2} cos (x) + \frac{1}{2} sin (x)

cos (x) cos (3 0^{\circ}) + sin (x) sin (3 0^{\circ})

化简

cos (3 0^{\circ}) : \frac{3}{2}

cos (3 0^{\circ})

使用以下普通恒等式:

cos (3 0^{\circ}) = \frac{3}{2}

cos (x)

周期表（周期为

36 0^{\circ} n

）：

x 0 3 0^{\circ} 4 5^{\circ} 6 0^{\circ} 9 0^{\circ} 12 0^{\circ} 13 5^{\circ} 15 0^{\circ} cos (x) 1 \frac{3}{2} \frac{2}{2} \frac{1}{2} 0 - \frac{1}{2} - \frac{2}{2} - \frac{3}{2} x 18 0^{\circ} 21 0^{\circ} 22 5^{\circ} 24 0^{\circ} 27 0^{\circ} 30 0^{\circ} 31 5^{\circ} 33 0^{\circ} cos (x) - 1 - \frac{3}{2} - \frac{2}{2} - \frac{1}{2} 0 \frac{1}{2} \frac{2}{2} \frac{3}{2}

= \frac{3}{2}

= \frac{3}{2} cos (x) + sin (3 0^{\circ}) sin (x)

化简

sin (3 0^{\circ}) : \frac{1}{2}

sin (3 0^{\circ})

使用以下普通恒等式:

sin (3 0^{\circ}) = \frac{1}{2}

sin (x)

周期表（周期为

36 0^{\circ} n

"）：

x 0 3 0^{\circ} 4 5^{\circ} 6 0^{\circ} 9 0^{\circ} 12 0^{\circ} 13 5^{\circ} 15 0^{\circ} sin (x) 0 \frac{1}{2} \frac{2}{2} \frac{3}{2} 1 \frac{3}{2} \frac{2}{2} \frac{1}{2} x 18 0^{\circ} 21 0^{\circ} 22 5^{\circ} 24 0^{\circ} 27 0^{\circ} 30 0^{\circ} 31 5^{\circ} 33 0^{\circ} sin (x) 0 - \frac{1}{2} - \frac{2}{2} - \frac{3}{2} - 1 - \frac{3}{2} - \frac{2}{2} - \frac{1}{2}

= \frac{1}{2}

= \frac{3}{2} cos (x) + \frac{1}{2} sin (x)

= \frac{3}{2} cos (x) + \frac{1}{2} sin (x)

\frac{\frac{3}{2} cos ( x ) + \frac{1}{2} sin ( x )}{\frac{3}{2} cos ( x ) - \frac{1}{2} sin ( x )} = \frac{1835}{726}

\frac{\frac{3}{2} cos ( x ) + \frac{1}{2} sin ( x )}{\frac{3}{2} cos ( x ) - \frac{1}{2} sin ( x )} = \frac{1835}{726}

两边减去

\frac{1835}{726}

\frac{\frac{3}{2} cos ( x ) + \frac{1}{2} sin ( x )}{\frac{3}{2} cos ( x ) - \frac{1}{2} sin ( x )} - \frac{1835}{726} = 0

化简

\frac{\frac{3}{2} cos ( x ) + \frac{1}{2} sin ( x )}{\frac{3}{2} cos ( x ) - \frac{1}{2} sin ( x )} - \frac{1835}{726} : \frac{- 1109 3 cos ( x ) + 2561 sin ( x )}{726 ( 3 cos ( x ) - sin ( x ) )}

\frac{\frac{3}{2} cos ( x ) + \frac{1}{2} sin ( x )}{\frac{3}{2} cos ( x ) - \frac{1}{2} sin ( x )} - \frac{1835}{726}

\frac{\frac{3}{2} cos ( x ) + \frac{1}{2} sin ( x )}{\frac{3}{2} cos ( x ) - \frac{1}{2} sin ( x )} = \frac{3 cos ( x ) + sin ( x )}{3 cos ( x ) - sin ( x )}

\frac{\frac{3}{2} cos ( x ) + \frac{1}{2} sin ( x )}{\frac{3}{2} cos ( x ) - \frac{1}{2} sin ( x )}

\frac{3}{2} cos (x) = \frac{3 cos ( x )}{2}

\frac{3}{2} cos (x)

分式相乘:

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

= \frac{3 cos ( x )}{2}

\frac{1}{2} sin (x) = \frac{sin ( x )}{2}

\frac{1}{2} sin (x)

分式相乘:

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

= \frac{1 \cdot sin ( x )}{2}

乘以:

1 \cdot sin (x) = sin (x)

= \frac{sin ( x )}{2}

= \frac{\frac{3}{2} cos ( x ) + \frac{1}{2} sin ( x )}{\frac{3 c o s ( x )}{2} - \frac{s i n ( x )}{2}}

\frac{3}{2} cos (x) = \frac{3 cos ( x )}{2}

\frac{3}{2} cos (x)

分式相乘:

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

= \frac{3 cos ( x )}{2}

\frac{1}{2} sin (x) = \frac{sin ( x )}{2}

\frac{1}{2} sin (x)

分式相乘:

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

= \frac{1 \cdot sin ( x )}{2}

乘以:

1 \cdot sin (x) = sin (x)

= \frac{sin ( x )}{2}

= \frac{\frac{3 c o s ( x )}{2} + \frac{s i n ( x )}{2}}{\frac{3 c o s ( x )}{2} - \frac{s i n ( x )}{2}}

合并分式

\frac{3 cos ( x )}{2} - \frac{sin ( x )}{2} : \frac{3 cos ( x ) - sin ( x )}{2}

使用法则

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

= \frac{3 cos ( x ) - sin ( x )}{2}

= \frac{\frac{3 c o s ( x )}{2} + \frac{s i n ( x )}{2}}{\frac{3 c o s ( x ) - s i n ( x )}{2}}

合并分式

\frac{3 cos ( x )}{2} + \frac{sin ( x )}{2} : \frac{3 cos ( x ) + sin ( x )}{2}

使用法则

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

= \frac{3 cos ( x ) + sin ( x )}{2}

= \frac{\frac{3 c o s ( x ) + s i n ( x )}{2}}{\frac{3 c o s ( x ) - s i n ( x )}{2}}

分式相除:

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

= \frac{( 3 cos ( x ) + sin ( x ) ) \cdot 2}{2 ( 3 cos ( x ) - sin ( x ) )}

约分:

2

= \frac{3 cos ( x ) + sin ( x )}{3 cos ( x ) - sin ( x )}

= \frac{3 cos ( x ) + sin ( x )}{3 cos ( x ) - sin ( x )} - \frac{1835}{726}

3 cos (x) - sin (x), 726

的最小公倍数:

726 (3 cos (x) - sin (x))

3 cos (x) - sin (x), 726

最小公倍数 (LCM)

计算出由出现在

3 cos (x) - sin (x)

或

726

中的因子组成的表达式

= 726 (3 cos (x) - sin (x))

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

726 (3 cos (x) - sin (x))

对于

\frac{3 cos ( x ) + sin ( x )}{3 cos ( x ) - sin ( x )} :

将分母和分子乘以

726

\frac{3 cos ( x ) + sin ( x )}{3 cos ( x ) - sin ( x )} = \frac{( 3 cos ( x ) + sin ( x ) ) \cdot 726}{( 3 cos ( x ) - sin ( x ) ) \cdot 726}

对于

\frac{1835}{726} :

将分母和分子乘以

3 cos (x) - sin (x)

\frac{1835}{726} = \frac{1835 ( 3 cos ( x ) - sin ( x ) )}{726 ( 3 cos ( x ) - sin ( x ) )}

= \frac{( 3 cos ( x ) + sin ( x ) ) \cdot 726}{( 3 cos ( x ) - sin ( x ) ) \cdot 726} - \frac{1835 ( 3 cos ( x ) - sin ( x ) )}{726 ( 3 cos ( x ) - sin ( x ) )}

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{( 3 cos ( x ) + sin ( x ) ) \cdot 726 - 1835 ( 3 cos ( x ) - sin ( x ) )}{726 ( 3 cos ( x ) - sin ( x ) )}

乘开

(3 cos (x) + sin (x)) \cdot 726 - 1835 (3 cos (x) - sin (x)) : - 11093 cos (x) + 2561 sin (x)

(3 cos (x) + sin (x)) \cdot 726 - 1835 (3 cos (x) - sin (x))

= 726 (3 cos (x) + sin (x)) - 1835 (3 cos (x) - sin (x))

乘开

726 (3 cos (x) + sin (x)) : 7263 cos (x) + 726 sin (x)

726 (3 cos (x) + sin (x))

使用分配律:

a (b + c) = ab + a c

a = 726, b = 3 cos (x), c = sin (x)

= 7263 cos (x) + 726 sin (x)

= 7263 cos (x) + 726 sin (x) - 1835 (3 cos (x) - sin (x))

乘开

- 1835 (3 cos (x) - sin (x)) : - 18353 cos (x) + 1835 sin (x)

- 1835 (3 cos (x) - sin (x))

使用分配律:

a (b - c) = ab - a c

a = - 1835, b = 3 cos (x), c = sin (x)

= - 18353 cos (x) - (- 1835) sin (x)

使用加减运算法则

- (- a) = a

= - 18353 cos (x) + 1835 sin (x)

= 7263 cos (x) + 726 sin (x) - 18353 cos (x) + 1835 sin (x)

化简

7263 cos (x) + 726 sin (x) - 18353 cos (x) + 1835 sin (x) : - 11093 cos (x) + 2561 sin (x)

7263 cos (x) + 726 sin (x) - 18353 cos (x) + 1835 sin (x)

同类项相加:

7263 cos (x) - 18353 cos (x) = - 11093 cos (x)

= - 11093 cos (x) + 726 sin (x) + 1835 sin (x)

同类项相加:

726 sin (x) + 1835 sin (x) = 2561 sin (x)

= - 11093 cos (x) + 2561 sin (x)

= - 11093 cos (x) + 2561 sin (x)

= \frac{- 1109 3 cos ( x ) + 2561 sin ( x )}{726 ( 3 cos ( x ) - sin ( x ) )}

\frac{- 1109 3 cos ( x ) + 2561 sin ( x )}{726 ( 3 cos ( x ) - sin ( x ) )} = 0

\frac{f ( x )}{g ( x )} = 0 \Rightarrow f (x) = 0

- 11093 cos (x) + 2561 sin (x) = 0

使用三角恒等式改写

- 11093 cos (x) + 2561 sin (x) = 0

在两边除以

cos (x), cos (x) \neq = 0

\frac{- 1109 3 cos ( x ) + 2561 sin ( x )}{cos ( x )} = \frac{0}{cos ( x )}

化简

- 11093 + \frac{2561 sin ( x )}{cos ( x )} = 0

使用基本三角恒等式:

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

- 11093 + 2561 tan (x) = 0

- 11093 + 2561 tan (x) = 0

将

11093

到右边

- 11093 + 2561 tan (x) = 0

两边加上

11093

- 11093 + 2561 tan (x) + 11093 = 0 + 11093

化简

2561 tan (x) = 11093

2561 tan (x) = 11093

两边除以

2561

2561 tan (x) = 11093

两边除以

2561

\frac{2561 tan ( x )}{2561} = \frac{1109 3}{2561}

化简

tan (x) = \frac{1109 3}{2561}

tan (x) = \frac{1109 3}{2561}

使用反三角函数性质

tan (x) = \frac{1109 3}{2561}

tan (x) = \frac{1109 3}{2561}

的通解

tan (x) = a \Rightarrow x = arctan (a) + 18 0^{\circ} n

x = arctan (\frac{1109 3}{2561}) + 18 0^{\circ} n

x = arctan (\frac{1109 3}{2561}) + 18 0^{\circ} n

以小数形式表示解

x = 0.64352 \dots + 18 0^{\circ} n

作图

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