f(x)h(x)=√2/2sin(x+pi/4)cos(x+5pi/4) =-√2/2sin(x+pi/4)cos(x+pi/4)√2/2sin(x+pi/4)cos(x+5pi/4) =-√2/2sin(x+pi/4)cos(x+pi/4)这个是怎么化出来的?
问题描述:
f(x)h(x)=√2/2sin(x+pi/4)cos(x+5pi/4) =-√2/2sin(x+pi/4)cos(x+pi/4)
√2/2sin(x+pi/4)cos(x+5pi/4) =-√2/2sin(x+pi/4)cos(x+pi/4)
这个是怎么化出来的?
答
f(x)h(x)=√2/2sin(x+pi/4)cos(x+5pi/4) =-√2/2sin(x+pi/4)cos(x+pi/4)cc
答
∵cos(x+5π/4)=cos[(x+π/4)+π]=-cos(x+π/4)
∴f(x)h(x)=√2/2sin(x+pi/4)cos(x+5pi/4) =-√2/2sin(x+pi/4)cos(x+pi/4)