tanα=-1/3 则sinα^2+2sinαcosα-3cosα^2=?

来源:学生作业帮助网 编辑:作业帮 时间:2024/07/28 13:45:21
tanα=-1/3 则sinα^2+2sinαcosα-3cosα^2=?
x)+I;V~c338#m#0#9F]c0gdkoTO;e -ԇ2Jzu*l%P@CHX@X 1}c JK 023/.H̳ a)

tanα=-1/3 则sinα^2+2sinαcosα-3cosα^2=?
tanα=-1/3 则sinα^2+2sinαcosα-3cosα^2=?

tanα=-1/3 则sinα^2+2sinαcosα-3cosα^2=?
tanα=-1/3 则tanα^2=1/9
(sinα^2+2sinαcosα-3cosα^2)/cosα^2
=1/tanα^2-3+2xtanα
=9-3+(-2/3)
=10/3
sinα/cosα=-1/3
sinα^2+cosα^2=1
cosα^2=9/10
sinα^2+2sinαcosα-3cosα^2=3