cosX+sinX=根号2sin(X+π/4)是怎么推出来的,

问题描述:

cosX+sinX=根号2sin(X+π/4)是怎么推出来的,

sinx+cosx
=√2(√2/2*sinx+√2/2cosx)
=√2(sinxcosπ/4+cosxsinπ/4)
=√2sin(x+π/4)