limx→0 xcot(4x)sin2x

limx→0 xcot(4x)sin2x = limx→0 x\frac{cos(4x)}{sin(4x)}sin2x = limx→0 x\frac{cos(4x)}{\frac{sin(4x)}{4x}}\frac{sin(2x)}{2x}2x = 1