Deriving The Quadratic Formula - Texas Instruments TI-89 Titanium Short User Manual

3. Define the expression for side
and store it in
w
Enter:
Define c(w)=
4. Use the
zeros( )
zeros of the first derivative of
the minimum value of
Note: The maximum length of the pole is
the minimum value of
5. Compute the exact maximum length of the
pole.
(2 ±)
Enter:
c
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
¸.

Deriving the Quadratic Formula

This activity shows you how to derive the quadratic formula:
±
– b
------------------------------------- -
x =
2a
Detailed information about using the functions in this example can be
found in Symbolic Manipulation.
90
.
c(w)
‡
(a(w)^2+b(w)^2)
function to compute the
c(w)
c(w)
2
b – 4ac
in terms of
c
to find
c(w)
.
.
Activities