Step 1:
\The function is
and the point is
.
Differentiate
with respect to
.

Chain rule of derivatives : 

Slope of the tangent line at
.

Slope of the tangent line is
.
Step 2:
\Point slope form of line equation is
.
Substitute
and
in the above equation.

The tangent line equation is
.
Solution :
\The tangent line equation is
.