Question

请问这道题目怎么做?

只要第一题的化简,谢谢

Answer 1

f(x)
=√3cos2x-2[cos(x+π/4)]^2 +1
=√3cos2x-{ 2[cos(x+π/4)]^2 -1 }
=√3cos2x-cos[2(x+π/4)]
=√3cos2x-cos(π/2 +2x)
=√3cos2x+ sin2x
=2sin(2x+π/3)