HP 39gs - Probability Functions

13-12 Using mathematical functions
POLYROOT Polynomial roots. Returns the roots for the nth-order
polynomial with the specified n+1 coefficients.
POLYROOT([coefficients])
Example
For x
4
+2x
3
–25x
2
–26x+120:
POLYROOT([1,2,-25,-26,120]) returns
[2,-3,4,-5].
HINT 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] 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!/(r!(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.
HP 39gs English.book Page 12 Wednesday, December 7, 2005 11:24 PM