SiNx > cosx, then the value range of X is 0

SiNx > cosx, then the value range of X is 0

1、 Image method: in the same coordinate system, draw the image of y = SiNx, y = cosx in [0,2 π]. From the image, we can see that when x ∈ (π / 4,5 π / 4), the image of y = SiNx is higher than that of y = cosx, so the solution set of SiNx > cosx in [0,2 π] is: (π / 4,5 π / 4); from the function y = SiNx, y = cosx are all minimum positive