The function is
and point is
.
Change of base formula for logarithm property :
.


Apply derivative on each side with respect to
.

.
Find slope at the point
.
Slope of the tangent line is derivative of the function at given point.
\Substitute
in
.
.
Slope of a tangent line is
.
Point - slope form of a line equation is
.
Substitute
and
in point - slope form.

.
The tangent line equation is
.
Graph :
\Graph the function
and tangent line is
:
The tangent line equation is
.