f(x) = sinx^4+cos^2x = sinx^4+1-sin^2x = 1-sin^2x(1-sin^2x) = 1 - sin^2xcos^2x= 1- (sinxcosx)^2= 1- (1/2sin2x)^2= 1- 1/4 sin^2(2x)= 1 - 1/4 * (1-cos4x)/2= 1/8 cos4x + 7/8最小正周期 = 2π/4 = π/2F(X) ...