Question

1.已知函数f(x)=2cos2x+sinx^2-4cosx,

Answer 1

1、 (1)、f(x)=4cosx^2-2+1-cosx^2-4cosx

=3cosx^2-4cosx-1 =3(cosx-2/3)^2-7/3

cos（π/3）=0.5 f(π/3)=-9/4

(2)、-1=