background image

Defining functions

 

 
You can assign a definition to a function using the CAS. 
 
As an example, define  
 

f

(

x

) = 

x

 + 

x

2

 + 

x

3

 
Type the expression on the right of 
the equals sign. Then, press the 

STO

 (or store) key. Type f(x). 

Remember that you need the 

ALPHA

 key to access f. 

 
Press 

ENTER

.  

 
Type f(1), and press 

ENTER

 
Evaluate the function for other values of 

x

 
You can also define functions of more than one variable.  
 
As an example, consider the formula for the volume of a cylinder 

V

 = 

π

r

2

h

 
Define a function 

v

(

r

h

) as 

π

r

2

h.

 

 
Evaluate 

v

(

r

h

) for various values of 

r

 and 

h

.  

 
 
 
 
 
 
 
If you would like the answer 
displayed as an approximate value, 
rather than a multiple of 

π

, you can 

select the 

MODE

 menu, scroll down 

to 

Exact/Approx

, and select 

APPROXIMATE

 

Tech Tip:

 when you are finished 

with the CAS, it is wise to return the 
display mode to 

AUTO

Summary of Contents for TI-92

Page 1: ...er This activity is designed to use the CAS on the TI 89 89T 92 calculator family to enhance understanding and instruction All screen shots are from the TI 89 This material may be used freely by teach...

Page 2: ...ear 2 Before using the CAS it is wise to clear the calculator of any values left in the memory by a previous use or user Press 2nd then F1 to access the F6 or Clean Up menu Select 2 NewProb Press ENTE...

Page 3: ...u move the cursor into the work space pressing the CLEAR key will clear the line that the cursor is on The CAS will remember lines even if they have disappeared off the top of the workspace You can us...

Page 4: ...Factoring expressions 1 Press F2 and select 2 factor Type 28x 21 followed by a close bracket Press ENTER Compare the result to the expansion in part 3 of the previous section 2 Try factoring some othe...

Page 5: ...e t Otherwise the CAS will treat at as a single variable with the name at Press ENTER Tech Tip the new form of the formula is sometimes displayed in an unusual manner Try solving other formulas such a...

Page 6: ...approach The next step is to divide both sides by 4 You can make use of the ANS key to do this 2 Open a bracket Type 2nd then to access ANS This tells the CAS to use the answer from the previous oper...

Page 7: ...he function for other values of x You can also define functions of more than one variable As an example consider the formula for the volume of a cylinder V r2 h Define a function v r h as r2 h Evaluat...

Reviews: