Question

Determine the points at which the graph of the function has a horizontal tangent line.

Answer 1

Step 1 :

The function is .

The tangent line of the function is horizontal, means that, the slope of the tangent line is zero.

Set slope = .

The function is .

Differentiate the function with respect to .

Apply quotient rule of derivatives : .

Apply power rule of derivatives : .

At , .

At , .

At the points the graph of the function has a horizontal tangent line.

Solution :

At the points the graph of the function has a horizontal tangent line.