Deriving the quadratic formula – Texas Instruments TITANIUM TI-89 User Manual

Page 743

Activities

743

Deriving the Quadratic Formula

This activity shows you how to derive the quadratic formula:

x =

4. Use the

zeros( )

function to compute the

zeros of the first derivative of

c(w)

to find

the minimum value of

c(w)

Note:

The maximum length of the pole is

the minimum value of

c(w)

5. Compute the exact maximum length of

the pole.

Enter:

(

2 ±)

6. Compute the approximate maximum

length of the pole.

Result: Approximately 20.8097 feet.

Note:

Use the auto-paste feature to copy

the result from step 4 to the entry line
inside the parentheses of c( ) and press

8 ¸.

–

4ac

–

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