# Modeling, Functions, and Graphs

## SectionB.1Getting Started

### SubsectionOn and Off

Press ON to turn on the calculator (see Figure B.1a). You will see a cursor blinking in the upper left corner of the Home screen. Press 2ndON to turn off the calculator.

### SubsectionNumbers and Operations

The parentheses keys, the Clear key, and the Enter key are shown in Figure B.1a. Locate the number keys, operation keys, and arrow keys on your calculator, as shown in Figure B.1b.
We use the - key for subtraction, but we use the (-) key (located next to ENTER) for negative numbers.

#### ExampleB.2.

Compute $$5 - 8\text{.}$$ Press
$$5$$ - $$8$$ENTER
Ans. $$-3$$

#### ExampleB.3.

Compute $$-5 + 8\text{.}$$ Press
(-)$$5$$ + $$8$$ENTER
Ans. $$3$$
We press ENTER to tell the calculator to compute.
The calculator has a key for the value of $$\pi\text{.}$$

#### ExampleB.4.

Compute $$2\pi\text{.}$$ Press
$$2$$X2nd ^ ENTER$$~~$$ or $$~~2$$2nd ^ ENTER
Ans. $$6.283185307$$

### SubsectionClear and Delete

Press DEL to delete the character under the cursor.
Press CLEAR to clear the contents of the current input line.
In the Home screen, press CLEAR CLEAR to clear the entire screen.

#### Troubleshooting.

1. If your screen is too light, press 2nd several times to make it darker. If it is too dark, press 2nd .
2. For the features we use in this book, the MODE and FORMAT should be in their default settings. Press MODE to see the menu in Figure B.2a, and 2nd ZOOM to see the format menu in Figure B.5b. Use the Arrow keys and ENTER to alter the menus to the default settings if necessary. Note: The Set Clock function does not appear on the T1-83.