数学cos2x+sin2x=根2sin(2x+π/4) .为什么?

问题描述:

数学cos2x+sin2x=根2sin(2x+π/4) .为什么?

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