将函数y=sin(7π/8-x)cos(x+π/8)的化简

将函数y=sin(7π/8-x)cos(x+π/8)的化简

原式=sin[π-(7π/8-x)]cos(x+π/8)
=sin(x+π/8)cos(x+π/8)
=1/2[2sin(x+π/8)cos(x+π/8)]
=1/2sin[2(x+π/8)]
=(1/2)sin(2x+π/4)