242 Appendix E: A Detailed Look at f

Calculate the integral in the expression for J4 (1),

π

0cos(4θ − sinθ )dθ

First, switch to Program mode and key in a subroutine that evaluates the function f(θ) = cos (4θ – sin θ).

Keystrokes

Display

 

¥

000-

Program mode.

´CLEAR M 000-

 

´b0

001–42,21, 0

4

002–

4

*

003–

20

®

004–

34

[

005–

23

-

006–

30

\

007–

24

n

008–

43 32

Now, switch to Run mode and key the limits of integration into the X- and Y-registers. Be sure the trigonometric mode is set to Radians, and set the display format to i2. Finally, press ´f0 to calculate the integral.

Keystrokes

Display

 

¥

 

 

0 v

0.0000

 

$

3.1416

 

R

3.1416

 

´i2

3.14

00

´f0

7.79

-03

®

1.45

-03

Run mode.

Keys lower limit into Y-register. Keys upper limit into X-register.

Sets the trigonometric mode to Radians.

Sets display format to i2. Integral approximated in i2.

Uncertainty of i2 approximation.