Using mathematical functions 13-3
Keyboard functions 
The most frequently used functions are available directly 
from the keyboard. Many of the keyboard functions also 
accept complex numbers as arguments.
,,, Add, Subtract, Multiply, Divide. Also accepts complex 
numbers, lists and matrices.
value1+ value2, etc.
e
x
Natural exponential. Also accepts complex numbers.
e^value
Example
e^5 returns 148.413159103
Natural logarithm. Also accepts complex numbers.
LN(value)
Example
LN(1) returns 0
!
For a description, see 
“COMB(5,2) returns 10. That is, 
there are ten different ways that 
five things can be combined two 
at a time.!” on page 13-12.
∑
For a description, see “Σ” on 
page 13-11.
EEX
For a description, see “Scientific 
notation (powers of 10)” on 
page 1-20.
For a description, see “ ” on 
page 11-7.
 
The multiplicative inverse 
function finds the inverse of a 
square matrix, and the 
multiplicative inverse of a real or 
complex number. Also works on 
a list containing only these object 
types. 
∫ ∫
x
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HP 39gs English.book  Page 3  Wednesday, December 7, 2005  11:24 PM