已知sinα-cosα=1/5,则sinαcosα的值为?
网友回答
sinα-cosα=1/5,则
(sinα-cosα)^2=1/25
(sinα)^2+(cosα)^2-2sinαcosα=1-2sinαcosα = 1/25
2sinαcosα = 24/25
sinαcosα=12/25
======以下答案可供参考======
供参考答案1:
sinα-cosα=1/5,
(sinα-cosα)^2=1/25
(sinα)^2+cosα)^2+2sinαcosα=1/25
1+2sinαcosα=1/25
2sinαcosα=-24/25
sinαcosα=-12/25
供参考答案2:
(sinα-cosα)^2=1-2sinαcosα=1/25
sinαcosα=12/25