Differentiate y =cos^4(x)
Let u = cos xdu/dx = -sin xy = u4dy/du = 4u3dy/dx = dy/du * du/dx = (4u3 ) * (-sin x) = 4 cos 3 x * -sin x = -4 cos 3 x sin x
CK
Let u = cos xdu/dx = -sin xy = u4dy/du = 4u3dy/dx = dy/du * du/dx = (4u3 ) * (-sin x) = 4 cos 3 x * -sin x = -4 cos 3 x sin x