Solving an equation on your Ti-89
- click the APPS button, or push 2nd-> ESC
- Go to the numeric solver on the menu, click enter.
- enter in the equation you want to solve, complete with an equals sign (if you moved everything to one side of the equation, put '=0')
- now hit enter.
- now it asks you if you know what "x" is. It will list the last value it gave for x on the last problem. Since we don't know what x is, just hit enter.
- now it asks you for bounds. usually you don't need to change this, but when solving a quadratic equation (one with your variable is squared or to another even power) it will only give you one of the values. (either the positive or negative value). If you know you need the positive value (for example) but it is giving you the negative one, then change the bounds so it looks like {0,1.E14}. If you want the negative value make it look like {-1.E14,0}
- now push the up arrow so you are over the "x=" value and hit F2. now it displays the value of your variable.
- Universal Tip: if you want to edit your equation, use the up arrow to highlight it, then push the left arrow to go to the left side of the entry, or the right arrow to go to the right side. (this can save you time, for example, if you want to edit the right side of a long equation).