HP 39gs Graphing manual Probability functions, Polyroot, Comb, Perm

POLYROOT	Polynomial roots. Returns the roots for the nth-order
	polynomial with the specified n+1 coefficients.
	POLYROOT([coefficients])
	Example
	For x4+2x3–25x2–26x+120:
	POLYROOT([1,2,-25,-26,120]) returns
	[2,-3,4,-5].
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]	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.

13-12 Using mathematical functions