1 tanα=(2tanα/2)/[1-(tanα/2)^2]=(2*2)/[1-2^2]=-4/32 (cosα+sinα)^2=(√袭坦2/4)^2 (cosα)^2+(sinα)^2+2sinαcosα=1/8 1+sin2α=1/8 sin2α=-7/拍雹桐肆码8