求证sinx-cosx=根号2sin(x-π/4)

问题描述:

求证sinx-cosx=根号2sin(x-π/4)

√2 sin(x-π/4)=√2(sinxcosπ/4-cosxsinπ/4)
=√2[(1/√2)sinx - (1/√2)cosx]
=sin x - cos x