Question

limit x-0 cos2x-cos3x/cos4x-1

Answer 1

Lim x-->0(cos3x - cos2x )/(1-cos4x)

Lim x -->0 (2sin5x/2.sin(-x/2)/2sin^2(2x)

Lim x-->0 {sin(5x/2).sin(-x/2)}/(sin^2(2x)

=> {5/2 × (-1/2)/4}

=> -5/16