(sec(x) / (sec(x)1))  (sec(x) / (sex(x)+1)) = 2cot(x)csc(x)
1 answer

On the left, get a common denominator of
(secx1)(secx+1) giving
secx(secx+1)secx(secx1) all over the denominator
which reduces to
2secx over the denominator
2secx/(sec^2x1)=
2secx*cos^2x/(1cos^2x)=2cosx/sin^2x
=2ctnx/sinx=2ctnx*cscx