已知tanα-1分之tanα=-1 求sin方α+sinαcosα+2
问题描述：
已知tanα-1分之tanα=-1 求sin方α+sinαcosα+2
答
tanα/(tanα-1)=-1tanα=1-tanα2tanα=1tanα=1/2sin²α+sinαcosα+2=(1-cos2α)/2+1/2sin2α+2=1/2-1/2*cos2α+1/2sin2α+2=-1/2*cos2α+1/2sin2α+5/2=-1/2*(1-tan²α)/(1+tan²α)+1/2*2tanα/(...