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求y=sinx+2sinxcosx-cosx的化简

题目详情
求y=sinx+2sinxcosx-cosx的化简
▼优质解答
答案和解析
y=sinx+2sinxcosx-cosx=(sinx-cosx)+[1-(sinx-cosx)²]/2=-(1/2)(sinx-cosx)²+(sinx-cosx)+1/2=-(1/2)[√2sin(x-π/4)]²+√2sin(x-π/4)+1/2=-sin²(x-π/4)+√2sin(x-π/4)+1/2