Here's the question you clicked on:
britbrat4290
Show that the equation is not an identity by finding a value of x for which both sides are defined but not equal. cos x - cos x sinx = cos3 x pi/4 or pi/2 ??????
cospi/2 = 0 soo thats not it
it would be 0... thank u
now that depends on of its \(\cos^3x\) or \(\cos 3x\)