Question 813090
<pre>
The other "solution" is NOT a solution.  Please ignore it!
He thought it was an equation to solve, so he made a bunch of errors
and got some crazy answer. Here's the way to prove the identity:


           {{{2tan(x)sec(x)}}}  =   {{{1/(1-sin(x))}}}{{{""-""}}}{{{1/(1+sin(x))}}}

                         {{{( (1+sin(x)) - (1-sin(x)))/((1-sin(x))(1+sin(x)))}}}

                         {{{(1+sin(x)-1+sin(x))/(1-sin^2(x))}}}

                         {{{2sin(x)/cos^2(x)}}}

                         {{{2sin(x)/(cos(x)cos(x))}}}

                         {{{2*expr(sin(x)/cos(x))*(1/cos(x))}}}

                         {{{2tan(x)sec(x)}}}
Edwin</pre>