The  functions are  and .

(a)

Find the value of .

Consider .

Differentiate with respect to  on each side.

.

Substitute  in the above expression.

.

Observe the graph of .

From the graph, .

.

Find  and .

 is the slope of the tangent line to the curve  at .

Consider two points on the tangent line to the curve   at .

The two points are  and .

Slope of the tangent line .

Slope of the tangent to the curve  at  is also same as the .

Thus, .

.

Substitute corresponding values in the above expression.

(b)

Find the value of  :

Consider .

Differentiate with respect to  on each side.

.

Substitute  in the above expression.

.

Find .

 is the slope of the tangent line to the curve  at .

Consider two points on the tangent line to the curve   at .

The two points are  and .

Slope of the tangent line is

.

.

.

Substitute  in above expression.

.

(a) .

(b) .