晕,直接问我嘛
cos^2(π-x)+sin(π+x)·cos(π-x)+2sin^2(x-π)
=cosx^2+(-sinx)(-cosx)+2sinx^2
=(1+2tanx+2tanx^2)/(1+tanx^2)
将1里的tanx算出代入就行了
晕,直接问我嘛
cos^2(π-x)+sin(π+x)·cos(π-x)+2sin^2(x-π)
=cosx^2+(-sinx)(-cosx)+2sinx^2
=(1+2tanx+2tanx^2)/(1+tanx^2)
将1里的tanx算出代入就行了