f(x)=sin^2x+sinxcosx-1/2,化简_数学解答

f(x)=sin^2x+sinxcosx-1/2,化简

人气：138 ℃　时间：2020-06-04 23:00:27

解答

f(x)=(1-cos2x)/2+1/2*sin2x-1/2
=1/2(sin2x-cos2x)
=√2/2*(sin2x*√2/2-cos2x*√2/2)
=√2/2(sin2xcosπ/4-cos2xsinπ/4)
=√2/2sin(2x-π/4)