(6)

Find at .

Observe the graph of the function .

Draw a tangent line to the curve at .

Slope of the tangent line is the derivative of the function at a particular point.

Slope of a tangent line with points and : .

The points on the tangent line are and .

Slope of the tangent line : .

Therefore .

Solution :

.

(7)

Find at .

Observe the graph of the function .

Draw a tangent line to the curve at .

Slope of the tangent line is the derivative of the function at a particular point.

Slope of a tangent line with points and : .

The points on the tangent line are and .

Slope of the tangent line : .

Therefore .

Solution :

.