### Home > APCALC > Chapter 3 > Lesson 3.4.4 > Problem 3-187

3-187.

HANAH STRIKES AGAIN!

To calculate the slope of a line tangent to at

*, most graphing calculators use Hanah’s method from problem 3-35, formally called the*

**symmetric difference quotient**, shown below.

Use the symmetric difference quotient to determine

if.Expand the numerator.

Combine like terms.

Factor out an.

Cancel out the.

Evaluate the limit.... this is.Use this symmetric difference in your graphing calculator to graph

forfor.Graph that on your calculator. Also sketch the derivative function you found in part (a). The sketches should look a lot alike.