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 .