sina=sin(-35π/6)=sin(-6π+π/6)=1/2 cosα=根号3/2
2sin(π＋α)cos(π-α)-cos(π+α)/( 1+sin^2α)+sin(π-α)-cos^2(π+α)
=2（-sinα)(-cosα）+cosα/（1+sin²α)+sinα-cos²α=根号3/2+(根号3/2)*4/5+1/2-3/4=9根号3/10-1/4