Step 1:
\The functions are
and
,
.
Consider
.
Apply derivative on each side with respect to
.

Consider
.
Apply derivative on each side with respect to
.

Step 2:
\Find
.

Substitute the values of
in above expression.

Step 3:
\Find slope of the tangent at
.
Substitute
in
.

.
Slope of a tangent line is
.
Find the point corresponding to the value
.
Substitute
in
.

Substitute
in
.

Now obtained point is 
Point - slope form of a line equation is
.
Substitute
and
in point - slope form.

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