Question 1204772
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Prove the identity of (sin4x-cos4x)/(1-cot4x)=sin4x
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<pre>
  {{{(sin(4x)-cos(4x))/(1-cot(4x))}}} = {{{(sin(4x)-cos(4x))/(1-cos(4x)/sin(4x))}}} = {{{(sin(4x)-cos(4x))/((sin(4x)-cos(4x))/(sin(4x)))}}} = 

          cancel common factors (sin(4x)-cos(4x)).  You will get then

= sin(4x).


QED.
</pre>

Solved.