Question 1114647
Start with the left side.


{{{(tanA+(secA-1))/(tanA-(secA-1))}}}


Try multiplying by  {{{(tanA+(secA-1))/(tanA+(secA-1))}}}.


{{{((tanA+(secA-1))^2)/((tanA)^2-(secA-1)^2)}}}


Just a start.  I have not gone any further with this.  Maybe you can and will finish.