=1-cos2x+sin2x 到√2sin(2x-π/4)+1的详细步骤!
问题描述:
=1-cos2x+sin2x 到√2sin(2x-π/4)+1的详细步骤!
为什么我看不懂怎么变成那样子的.最好加上用了哪个公式.
答
1-cos2x+sin2x=sin2x-cos2x+1=(√2)[(√2/2)sin2x-(√2/2)cos2x]+1【(√2)×(√2/2)=2/2=1】=(√2)[sin2xcos(π/4)-cos2xsin(π/4)]+1=(√2)sin(2x-π/4)+1【用了公式:sin(α-β)=sinαcosβ-cosαsinβ】...