Prove that
.
Consider
.
Apply derivative on each side with respect to
.

.
Derivative of inverse Trigonometric functions :
and 





The function is
.
For all values of
,
, a constant.
Since the derivative of the function
.
To find the value of
,substitute
in left side of the function
.



To find the value of
,substitute
in left side of the function
.



Therefore,
.
.