These are questions that students in classes that use the TI-89 often ask. If you are having a particular difficulty, it is likely the answer to your question is in the list below. Links to particular sections are included to help you find the answer you need.

### 1. My graph doesn't look right. Why not?

When a graph doesn't "look right" it is most likely because you have either entered the function incorrectly or you have not set the window properly.

### 2. The graph is not showing on the screen. What's wrong?

There are two main reasons that a graph may not show up.

a) The function may be turned off. From the Y=Editor window turn functions off by pressing F5 and make a selection. You can also press F4 to select a single function to be turned on.

b) Your window may not be set correctly.

### 3. The graph has no axes. How do I turn them on?

The axes can be turned on and off with the FORMAT menu.

### 4. Why am I getting the message ERR0R 12: DIM MISMATCH?

This message is shown when you have a statistical plot turned on and there are no values in lists to graph or they are not evenly matched. You need to turn the plot off.

### 5. Why does my trace have different coordinates?

The FORMAT setting will determine whether rectangular or polar coordinates are shown.

### 6. When I try to graph a function the screen has r1 or x1t and y1t on it instead of y1. How do I get a y1?

The MODE setting will determine the type of graph that can be drawn.

### 7. Why can't I enter the values I want to in the TABLE?

The TABLE must be set to ASK before you can enter the values you want.

### 8. Can I solve an equation or check an equation using a graph?

You can solve an equation if you can enter both sides of the equation into the graph editor and use intersect to find the solution.

### 9. How can I check an answer to an equation on the Home Screen?

You can store the answer in the variable X and then enter the expression to check your answer.

### 10. How can I edit a line without having to retype the entire expression?

You can use the storage area ENTRY to recall several recent entries.

### 11. I'm entering an expression in the home screen but the answer is wrong. How can I correct this entry?

There is a good chance that your expression has not been entered with the proper placement of parentheses. You must enter parentheses to maintain the proper order of operations.

### 12. How can I make the screen darker or lighter?

Press to lighten the screen, and to darken the screen.

### 13. I can't remember where a function is. What do I do?

The CATALOG menu has every function, variable, list, etc. in the catalog. You may want to create a CUSTOM menu.