These are questions that students in classes that use the TI-86 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. Make sure that the equal sign is dark. If not, then move the cursor to the equal sign and press enter to turn the function 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?

Use the cursor and the key to lighten or darken a 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 enter frequently used functions in the CUSTOM menu.