2.3  Formulas          Homework: Odds 1-33

Nancy J. McCormick's Home Page

DSPM 0800 Class Notes

· Evaluating formulas:  Replace the variable with a given value & compute.
(You can use the grapher when there is only one independent variable).

Example:

This formula is used to determine how many milligrams of a 400 mg dose of ibuprofen remains in the bloodstream after t hours when t is between 0 and 6. Use the grapher to determine how much ibuprofen is in the bloodstream after 1 hr? after 2 hrs? after 3 hrs? after 4 hrs? after 5 hrs? after 6 hrs?

Enter formula into the grapher replacing “t” with “x” as follows:

Go to 2nd TBLSET, enter 0 for TblStart, enter 1 for Tbl, enter Ask for Indpnt, and enter Auto for Depend as follows:

Go to 2nd TABLE. If there are already entries there, enter DEL for each entry in the X column to clear the table.
Now enter the following values for x: 1, 2, 3, 4, 5, and 6. The table then gives the corresponding values in the Y column so that we can answer the questions asked as shown in the table.


Example: The wavelength of a musical note is given by the formula

where 344 is the speed of sound in meters per second and f is the frequency of the sound in cycles per second.
What is the wavelength of a sound with frequency 24 cycles per second?, 15 cycles per second? 52 cycles per second?

 meters       meters       meters

As the frequency increases, what happens to the wavelength?

Example: The formula for interest on money borrowed is given by

where P is the principal borrowed, r is the rate of interest, and t is the time, in years, over which the money is repaid.
What is the amount of interest if $4000 is borrowed at a rate of 8% for 2 years.

How much would your monthly payment be?


· Solving a formula for a given letter:
        Clear denominators.
        Isolate the term having the letter.
        Divide by the coefficient (multiplier) of the letter.

Example:

Example: 




Example:




Example:




TOP