f(x)=cos2x+sin2x a=90
g(x)=f(2x+90)=cos(2x+90)+sin(2x+90)=co2x-sin2x
h(x)=f(x)g(x)=(cos2x+sin2x)(cos2x-sin2x)=cos4x
对的对的,没注意到,不好意思哈
f(x)=cos2x+sin2x a=90
g(x)=f(2x+90)=cos(2x+90)+sin(2x+90)=co2x-sin2x
h(x)=f(x)g(x)=(cos2x+sin2x)(cos2x-sin2x)=cos4x
对的对的,没注意到,不好意思哈