解
sin(A)−0.1⋅cos(A)=9.86.94
解
A=2.45933…+2πn,A=0.88159…+2πn
+1
度
A=140.90941…∘+360∘n,A=50.51177…∘+360∘n解答ステップ
sin(A)−0.1cos(A)=9.86.94
両辺に0.1cos(A)を足すsin(A)=0.70816…+0.1cos(A)
両辺を2乗するsin2(A)=(0.70816…+0.1cos(A))2
両辺から(0.70816…+0.1cos(A))2を引くsin2(A)−0.50149…−0.14163…cos(A)−0.01cos2(A)=0
三角関数の公式を使用して書き換える
−0.50149…+sin2(A)−0.01cos2(A)−0.14163…cos(A)
ピタゴラスの公式を使用する: cos2(x)+sin2(x)=1sin2(x)=1−cos2(x)=−0.50149…+1−cos2(A)−0.01cos2(A)−0.14163…cos(A)
簡素化 −0.50149…+1−cos2(A)−0.01cos2(A)−0.14163…cos(A):−1.01cos2(A)−0.14163…cos(A)+0.49850…
−0.50149…+1−cos2(A)−0.01cos2(A)−0.14163…cos(A)
類似した元を足す:−cos2(A)−0.01cos2(A)=−1.01cos2(A)=−0.50149…+1−1.01cos2(A)−0.14163…cos(A)
数を足す/引く:−0.50149…+1=0.49850…=−1.01cos2(A)−0.14163…cos(A)+0.49850…
=−1.01cos2(A)−0.14163…cos(A)+0.49850…
0.49850…−0.14163…cos(A)−1.01cos2(A)=0
置換で解く
0.49850…−0.14163…cos(A)−1.01cos2(A)=0
仮定:cos(A)=u0.49850…−0.14163…u−1.01u2=0
0.49850…−0.14163…u−1.01u2=0:u=−2.020.14163…+2.03401…,u=2.022.03401…−0.14163…
0.49850…−0.14163…u−1.01u2=0
標準的な形式で書く ax2+bx+c=0−1.01u2−0.14163…u+0.49850…=0
解くとthe二次式
−1.01u2−0.14163…u+0.49850…=0
二次Equationの公式:
次の場合: a=−1.01,b=−0.14163…,c=0.49850…u1,2=2(−1.01)−(−0.14163…)±(−0.14163…)2−4(−1.01)⋅0.49850…
u1,2=2(−1.01)−(−0.14163…)±(−0.14163…)2−4(−1.01)⋅0.49850…
(−0.14163…)2−4(−1.01)⋅0.49850…=2.03401…
(−0.14163…)2−4(−1.01)⋅0.49850…
規則を適用 −(−a)=a=(−0.14163…)2+4⋅1.01⋅0.49850…
指数の規則を適用する: n が偶数であれば (−a)n=an(−0.14163…)2=0.14163…2=0.14163…2+4⋅0.49850…⋅1.01
数を乗じる:4⋅1.01⋅0.49850…=2.01395…=0.14163…2+2.01395…
0.14163…2=0.02005…=0.02005…+2.01395…
数を足す:0.02005…+2.01395…=2.03401…=2.03401…
u1,2=2(−1.01)−(−0.14163…)±2.03401…
解を分離するu1=2(−1.01)−(−0.14163…)+2.03401…,u2=2(−1.01)−(−0.14163…)−2.03401…
u=2(−1.01)−(−0.14163…)+2.03401…:−2.020.14163…+2.03401…
2(−1.01)−(−0.14163…)+2.03401…
括弧を削除する: (−a)=−a,−(−a)=a=−2⋅1.010.14163…+2.03401…
数を乗じる:2⋅1.01=2.02=−2.020.14163…+2.03401…
分数の規則を適用する: −ba=−ba=−2.020.14163…+2.03401…
u=2(−1.01)−(−0.14163…)−2.03401…:2.022.03401…−0.14163…
2(−1.01)−(−0.14163…)−2.03401…
括弧を削除する: (−a)=−a,−(−a)=a=−2⋅1.010.14163…−2.03401…
数を乗じる:2⋅1.01=2.02=−2.020.14163…−2.03401…
分数の規則を適用する: −b−a=ba0.14163…−2.03401…=−(2.03401…−0.14163…)=2.022.03401…−0.14163…
二次equationの解:u=−2.020.14163…+2.03401…,u=2.022.03401…−0.14163…
代用を戻す u=cos(A)cos(A)=−2.020.14163…+2.03401…,cos(A)=2.022.03401…−0.14163…
cos(A)=−2.020.14163…+2.03401…,cos(A)=2.022.03401…−0.14163…
cos(A)=−2.020.14163…+2.03401…:A=arccos(−2.020.14163…+2.03401…)+2πn,A=−arccos(−2.020.14163…+2.03401…)+2πn
cos(A)=−2.020.14163…+2.03401…
三角関数の逆数プロパティを適用する
cos(A)=−2.020.14163…+2.03401…
以下の一般解 cos(A)=−2.020.14163…+2.03401…cos(x)=−a⇒x=arccos(−a)+2πn,x=−arccos(−a)+2πnA=arccos(−2.020.14163…+2.03401…)+2πn,A=−arccos(−2.020.14163…+2.03401…)+2πn
A=arccos(−2.020.14163…+2.03401…)+2πn,A=−arccos(−2.020.14163…+2.03401…)+2πn
cos(A)=2.022.03401…−0.14163…:A=arccos(2.022.03401…−0.14163…)+2πn,A=2π−arccos(2.022.03401…−0.14163…)+2πn
cos(A)=2.022.03401…−0.14163…
三角関数の逆数プロパティを適用する
cos(A)=2.022.03401…−0.14163…
以下の一般解 cos(A)=2.022.03401…−0.14163…cos(x)=a⇒x=arccos(a)+2πn,x=2π−arccos(a)+2πnA=arccos(2.022.03401…−0.14163…)+2πn,A=2π−arccos(2.022.03401…−0.14163…)+2πn
A=arccos(2.022.03401…−0.14163…)+2πn,A=2π−arccos(2.022.03401…−0.14163…)+2πn
すべての解を組み合わせるA=arccos(−2.020.14163…+2.03401…)+2πn,A=−arccos(−2.020.14163…+2.03401…)+2πn,A=arccos(2.022.03401…−0.14163…)+2πn,A=2π−arccos(2.022.03401…−0.14163…)+2πn
元のequationに当てはめて解を検算する
sin(A)−0.1cos(A)=9.86.94 に当てはめて解を確認する
equationに一致しないものを削除する。
解答を確認する arccos(−2.020.14163…+2.03401…)+2πn:真
arccos(−2.020.14163…+2.03401…)+2πn
挿入 n=1arccos(−2.020.14163…+2.03401…)+2π1
sin(A)−0.1cos(A)=9.86.94の挿入向けA=arccos(−2.020.14163…+2.03401…)+2π1sin(arccos(−2.020.14163…+2.03401…)+2π1)−0.1cos(arccos(−2.020.14163…+2.03401…)+2π1)=9.86.94
改良0.70816…=0.70816…
⇒真
解答を確認する −arccos(−2.020.14163…+2.03401…)+2πn:偽
−arccos(−2.020.14163…+2.03401…)+2πn
挿入 n=1−arccos(−2.020.14163…+2.03401…)+2π1
sin(A)−0.1cos(A)=9.86.94の挿入向けA=−arccos(−2.020.14163…+2.03401…)+2π1sin(−arccos(−2.020.14163…+2.03401…)+2π1)−0.1cos(−arccos(−2.020.14163…+2.03401…)+2π1)=9.86.94
改良−0.55293…=0.70816…
⇒偽
解答を確認する arccos(2.022.03401…−0.14163…)+2πn:真
arccos(2.022.03401…−0.14163…)+2πn
挿入 n=1arccos(2.022.03401…−0.14163…)+2π1
sin(A)−0.1cos(A)=9.86.94の挿入向けA=arccos(2.022.03401…−0.14163…)+2π1sin(arccos(2.022.03401…−0.14163…)+2π1)−0.1cos(arccos(2.022.03401…−0.14163…)+2π1)=9.86.94
改良0.70816…=0.70816…
⇒真
解答を確認する 2π−arccos(2.022.03401…−0.14163…)+2πn:偽
2π−arccos(2.022.03401…−0.14163…)+2πn
挿入 n=12π−arccos(2.022.03401…−0.14163…)+2π1
sin(A)−0.1cos(A)=9.86.94の挿入向けA=2π−arccos(2.022.03401…−0.14163…)+2π1sin(2π−arccos(2.022.03401…−0.14163…)+2π1)−0.1cos(2π−arccos(2.022.03401…−0.14163…)+2π1)=9.86.94
改良−0.83534…=0.70816…
⇒偽
A=arccos(−2.020.14163…+2.03401…)+2πn,A=arccos(2.022.03401…−0.14163…)+2πn
10進法形式で解を証明するA=2.45933…+2πn,A=0.88159…+2πn