limx→0(1−cos2x)sin5xx2sin3x=
103
310
65
56
limx→0(1−cos2x)sin5xx2sin3x =limx→02sin2xsin5xx2sin3x =limx→02sin2xx2(sin5x5x)×5(sin3x3x)3 =10×12×11×3 =103