Question

sin²（π/4+x)怎样等于cos²（π/4-x)?

Answer 1

sin（π/4+x)=cos（π/2-（π/4+x)=cos（π/4-x）函数名奇变偶不变
再平方∴sin²（π/4+x)=cos²（π/4-x)

Answer 2

∵sin（π/4+x)
=cos[π/2-(π/4+x)]
=cos（π/4-x)
∴sin²（π/4+x)=cos²（π/4-x)