Modes and settings

6.1The MODE screen#

Press mode to see the settings. The chosen option on each row is in [brackets]. Move between rows with ▲ and ▼, between options with ◀ and ▶, and press enter to choose the option under the cursor. Press 2ndQUITmode to go home.

6.2Normal, scientific and engineering notation#

NORMAL shows numbers the usual way and switches to scientific notation only for very big or small values. SCI always shows one digit before the point, as in 1.234E3. ENG uses powers of ten that are multiples of 3, as in 12.345E3.

Example 6.1

Scientific notation

$$1234=1.234\times10^{3}$$

1. In MODE press right once on the first row (SCI), enter, and return home.

   mode▶enter2ndQUITmode

2. Type 1234.

   1234enter

Example 6.2

Engineering notation

1. Choose ENG (right twice on the first row).

   mode▶▶enter2ndQUITmode

2. Type 12345.

   12345enter

6.3Fix the number of decimal places#

FLOAT shows as many decimals as are needed (up to 10 digits). Choosing a number from 0 to 9 rounds every answer to that many decimals. The options on the second row are FLOAT, 0, 1, … 9 so 2 decimals is three steps right of FLOAT.

Example 6.3

Two decimal places

1. In MODE move down one row and right 3 times to the 2, enter, go home.

   mode▼▶▶▶enter2ndQUITmode

2. Type 1/3.

   1÷3enter

Example 6.4

Zero decimals rounds to a whole number

1. Choose 0 on the second row (right once).

   mode▼▶enter2ndQUITmode

2. Type 2.5.

   2.5enter

The indicator strip shows FIX 2 (or the number you chose). Go back to FLOAT to see full precision again.

6.4Radian or degree#

Choose DEGREE when angles are in degrees (triangles, most school problems) and RADIAN for calculus, π and graphs of trig functions. The current unit is always shown in the indicator strip.

Example 6.5

Switch to degrees

1. In MODE move down 2 rows, right once to DEGREE, enter, home.

   mode▼▼▶enter2ndQUITmode

2. Type tan(45).

   tan45)enter

Example 6.6

Radian mode (default)

1. Type tan(π/4).

   tan2ndπ^÷4)enter

6.5Graph type and line style#

FUNC graphs y in terms of x, PAR graphs x and y in terms of t, and POL graphs r in terms of θ. The Y= editor, WINDOW screen and trace all change to match. CONNECTED joins the points of a graph into a curve; DOT draws separate dots.

Example 6.7

Parametric mode changes the Y= editor

1. In MODE move down 3 rows, right once to PAR, enter, and press the Y= key.

   mode▼▼▼▶entery=

Example 6.8

Polar mode

1. Choose POL (right twice on the fourth row) and open Y=.

   mode▼▼▼▶▶entery=

See also Graphing functions: Graph parametric equations

6.6Real or complex results#

In REAL mode a calculation whose answer is not real, such as the square root of −4, gives a NONREAL ANS error. In a+bi mode the answer is shown as 2i. In re^θi mode complex answers are shown in polar form.

Example 6.9

Error in real mode

1. Type √(−4) in REAL mode.

   2nd√x²(−)4)enter

Example 6.10

Allow complex answers

1. In MODE move down 5 rows, right once to a+bi, enter, home.

   mode▼▼▼▼▼▶enter2ndQUITmode

2. Type √(−4).

   2nd√x²(−)4)enter

Example 6.11

Polar form of a complex number

1. Choose re^θi (right twice on the sixth row).

   mode▼▼▼▼▼▶▶enter2ndQUITmode

2. Type 2i using 2nd dot for i.

   22ndi.enter

See also Complex numbers

6.7Statistics diagnostics#

With STAT DIAGNOSTICS ON, regressions also show r and r² (or R²). Turn them OFF to see only the coefficients. The setting is on the ninth row.

Example 6.12

Diagnostics off

1. In MODE move down 8 rows, press left to OFF and enter.

   mode▼▼▼▼▼▼▼▼◀enter