2sin²x+sinxcosx+cos²x
=sin²x+sinxcosx+1
=（1-cos2x）/2+sin2x/2+1
=sin2x/2-cos2x/2+3/2
=√2/2（√2/2sin2x-√2/2cos2x）+3/2
=√2/2sin（2x-π/4）+3/2
如果本题有什么不明白可以追问,