来自苟秉宸的问题
已知tanα=3,则(sinα)平方-(cosα)平方=
已知tanα=3,则(sinα)平方-(cosα)平方=
1回答
2020-06-24 06:48
已知tanα=3,则(sinα)平方-(cosα)平方=
已知tanα=3,则(sinα)平方-(cosα)平方=
tanα=3,
(sinα)^2-(cosα)^2=(sinα)^2-(cosα)^2)/(sinα)^2+(cosα)^2)
=(tan^2α-1)/(tan^2α+1)
=(9-1)/(9+1)
=4/5