化简：2sin(πx/8+π/4)+sin(-πx/8+π/4)=

2sin(πx/8+π/4)+sin(-πx/8+π/4)
=2sin(πx/8)cos(π/4)+2cos(πx/8)sin(π/4)+sin(-πx/8)cos(π/4)+cos(-πx/8)sin(π/4)
=2^0.5/2(2sin(πx/8)+2cos(πx/8)-sin(πx/8)+cos(πx/8))
=2^0.5/2(sin(πx/8)+3cos(πx/8))
=2^0.5*10^0.5/2(1/10^0.5sin(πx/8)+3/10^0.5cos(πx/8))
令cosa=1/10^0.5 sina=3/10^0.5
=5^0.5(sin(πx/8)cosa+cos(πx/8))sina)
=5^0.5sin(πx/8+a)
=5^0.5sin(πx/8+arcsin(3/10^0.5))