The Equation Solver – This can be a nice option for solving algebra problems – but it is not a “no brainer”—you have to think about what you are doing!

1. Open the MATH menu and highlight the 10^th option, Solver (Easiest way to get to this function is to arrow up once after you hit the Math button).

2. Press ENTER to open the Solver screen and then press the up arrow to open the equation screen. (see screen shot below)

3. Type the equation in the form of 0= and then press ENTER. (Example from screen shot below 0=x^2 – 52x-93). WARNING—hitting ENTER does not solve the equation, it merely opens the next screen. The “x=” value displayed is the last thing your calculator had x equal to, it is NOT a solution to the equation.

4. All the variables used in your equation will be listed – most of the time you will only have one variable “x”. You can specify values for all of them; the value assigned to the unknown is an "initial guess" for its value. If you do not specify a value, the calculator will use the last value it had stored for that variable. This “initial guess” will be where the calculator starts looking for solutions to the problem. Usually, for physics problems, you are not looking for a negative answer—so you may find it useful to put in a large positive number for the “x=” value.

5. Place the cursor on the “x=” line and press ALPHA- ENTER. After a few seconds the TI-83 updates the unknown with its (true) approximate value.

Solver Screen	Initial Guess x=0

An equation may have multiple mathematical solutions, so you must remember that a mathematical solution may not be an appropriate physical solution. Your choice of an initial guess influences which solution the TI-83 produces. Choosing a large positive value for the “x equals” line may be helpful in “encouraging” the calculator to give a positive solution to the equation. In addition, a way to limit the search is to alter the last line- the “bound” line; it specifies the interval in which you seek a solution. If you know you are looking for a positive value you can set the bound = {0, 1E99}; then the calculator will only look at positive values for solutions to the equation. If you change the “bound” line make sure to place the cursor back on the “x=” line before you hit Alpha – Enter, also make sure your “initial guess” ( aka the “x=” value) is within the bounds. If the “initial guess” is not in the bounds you will get an error message that says “bad guess”, other error messages such as “sign change” mean there is something wrong with your equation. 

Initial solving returns a Negative solution for x	After Changing bounds a + solution for x is found