(a)

The function is  and point is .

Apply derivative on each side with respect to .

Constant multiplication and power rule : .

.

Find the slope of the tangent line at .

Substitute in .

.

Therefore, slope of the tangent line is .

Point-slope form of line equation is .

Substitute and in the point-slope form.

The tangent line equation is .

(b)

Graph the function and the tangent line :

(c)

Graph of the function using derivative feature of a graphing utility.

The tangent line equation is .