2sin²α+3sinαcosα-cos²α

1个回答

化简吗?
原式=2*(1-cos2α)/2+3/2*sin2α-(1+cos2α)/2
=3/2*sin2α-3/2*cos2α+1/2
=3/2*(sin2α-cos2α)+1/2
=3√2/2*sin(2α-π/4)+1/2