H I N T The results of POLYROOT will often not be easily seen in HOME due to the number of decimal places, especially if they are complex numbers. It is better to store the results of POLYROOT to a matrix.

For example, POLYROOT([1,0,0,-8] 672?_￿M1 will store the three complex cube roots of 8 to matrix M1 as a complex vector. Then you can see them easily by going to the Matrix Catalog. and access them individually in calculations by referring to M1(1), M1(2) etc.

Probability functions

COMB

Number of combinations (without regard to order) of n things

 

taken r at a time: n!/(r!(n−r)).

 

COMB(n,r)

 

Example

 

COMB(5,2) returns 10. That is, there are ten different

 

ways that five things can be combined two at a time.

!

Factorial of a positive integer. For non-integers, ! = Γ(x + 1).

 

This calculates the gamma function.

 

value!

PERM

Number of permutations (with regard to order) of n things

 

taken r at a time: n!/ (n-r)!.

 

PERM (n,r)

 

Example

 

PERM(5,2) returns 20. That is, there are 20 different

 

permutations of five things taken two at a time.

RANDOM

Random number (between zero and 1). Produced by a pseudo-

 

random number sequence. The algorithm used in the

 

RANDOM function uses a “seed” number to begin its

 

sequence. To ensure that two calculators must produce

 

different results for the RANDOM function, use the

 

RANDSEED function to seed different starting values before

 

using RANDOM to produce the numbers.

 

RANDOM

Using mathematical functions

10-13