cos(A)=0.7865

解

cos (A) = 0.7865

A = 0.66567 \dots + 2 πn, A = 2 π - 0.66567 \dots + 2 πn

度

A = 38.14037 \dots^{\circ} + 36 0^{\circ} n, A = 321.85962 \dots^{\circ} + 36 0^{\circ} n

解答ステップ

cos (A) = 0.7865

三角関数の逆数プロパティを適用する

cos (A) = 0.7865

以下の一般解

cos (A) = 0.7865

cos (x) = a \Rightarrow x = arccos (a) + 2 πn, x = 2 π - arccos (a) + 2 πn

A = arccos (0.7865) + 2 πn, A = 2 π - arccos (0.7865) + 2 πn

A = arccos (0.7865) + 2 πn, A = 2 π - arccos (0.7865) + 2 πn

10進法形式で解を証明する

A = 0.66567 \dots + 2 πn, A = 2 π - 0.66567 \dots + 2 πn