Question

f(x)是以5為周期的奇函數(shù)，f(-3)=4,且cosα=,則f(4cos2α)=____________.

Answer 1

解析:f(4cos2α)=f［4(2cos²α-1）］=f［4×2×()²-4］=f(-2)

=f(-5+3)=f(3)=-f(-3)=-4.

答案:-4