(a) The equation is .

Find .

Apply  on each side.

Differentiate with respect to .

.

(b)

Find the slope of the tangent line.

Derivative of the function is slope of the tangent line.

(i) At the point  :

Substitute  in .

 when .

(ii) At the point :

Substitute  in .

.

(iii) At the point :

Substitute  in .

.

(c)

Tangent line will not exist at a point if the derivative at that point does not exist.

Derivative will not exist if denominator is zero.

At ,  is undefined.

(a) .

(b)  when ; ; .

(c) .