2sin²α+2sinαcosα-cos²α 化简

2sin²α+2sinαcosα-cos²α 化简
2sin²α+2sinαcosα-cos²α 化简

2sin²α+2sinαcosα-cos²α 化简
2sin²α+2sinαcosα-cos²α
=-(cos^2α-sin^a)+sin^2a+sin2α
=-cos2α-1/2(-2sin^2a+1-1)+sin2α
=-cos2α-1/2cos2α+1/2+sin2a
=-3/2cos2a+sin2a+1/2