Question 868103
Start with the definition of csc on the left and make steps.


{{{1/sin(t)-sin(t)}}}
{{{(1-sin^2(t))/sin(t)}}}
{{{cos^2(t)/sin(t)}}}------most basic pythagorean triangle identity
{{{cos(t)*(cos(t)/sin(t))}}}
{{{cos(t)cot(t)}}}. DONE.