f(x)=(sinx+cosx)²+2cos2x-2
= sin²x+cos²x+2sinxcosx+2cos2x - 2
= 1+2sinxcosx+2cos2x - 2
= 2sinxcosx+2cos2x - 1
= sin2x+2cos2x-1
令cost=1/√5，sint=2/√5
f(x) = √5(sin...
已知函数f(x)=(sinx+coss)2+2cos2x-2
f(x)=(sinx+cosx)²+2cos2x-2
= sin²x+cos²x+2sinxcosx+2cos2x - 2
= 1+2sinxcosx+2cos2x - 2
= 2sinxcosx+2cos2x - 1
= sin2x+2cos2x-1
令cost=1/√5，sint=2/√5
f(x) = √5(sin...