sin(A)= 4/5 ,sin(2A)

解答

sin (A) = \frac{4}{5}, sin (2 A)

A \in R 无解

求解步骤

sin (A) = \frac{4}{5}, sin (2 A)

使用反三角函数性质

sin (A) = \frac{4}{5}

sin (A) = \frac{4}{5}

的通解

sin (x) = a \Rightarrow x = arcsin (a) + 2 πn, x = π - arcsin (a) + 2 πn

A = arcsin (\frac{4}{5}) + 2 πn, A = π - arcsin (\frac{4}{5}) + 2 πn

A = arcsin (\frac{4}{5}) + 2 πn, A = π - arcsin (\frac{4}{5}) + 2 πn

在

sin (2 A)

范围内的解

A \in R 无解

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