Question 360872
<pre><b>

{{{sin(theta)/(1-cos(theta))}}}{{{""-""}}}{{{(1+cos(theta))/sin(theta)}}}{{{""=""}}}{{{0}}}

Multiply the first term by the conjugate of the denominator over
itself:

{{{expr(sin(theta)/(1-cos(theta)))red(expr(  (1+cos(theta))/(1+cos(theta)) ))}}}{{{""-""}}}{{{(1+cos(theta))/sin(theta)}}}{{{""=""}}}{{{
0}}}

{{{ (sin(theta)(1+cos(theta)))/(1-Cos^2theta)}}}{{{""-""}}}{{{
(1+cos(theta))/sin(theta)}}}{{{""=""}}}{{{
0}}}

{{{ (sin(theta)(1+cos(theta)))/(Sin^2theta)}}}{{{""-""}}}{{{
(1+cos(theta))/sin(theta)}}}{{{""=""}}}{{{
0}}}


{{{ (cross(sin(theta))(1+cos(theta)))/(Sin^cross(2)theta)}}}{{{""-""}}}{{{(1+cos(theta))/sin(theta)}}}{{{""=""}}}{{{
0}}}


{{{ (1+cos(theta))/(sin(theta))}}}{{{""-""}}}{{{
(1+cos(theta))/sin(theta)}}}{{{""=""}}}{{{
0}}}


{{{ ((1+cos(theta))-(1+cos(theta)))/sin(theta)}}}{{{""=""}}}{{{
0}}}

{{{ (1+cos(theta)-1-cos(theta))/sin(theta)}}}{{{""=""}}}{{{
0}}}

{{{0}}}{{{""=""}}}{{{0}}}

Edwin</pre>