Texas Instruments TI-83 PLUS - Manual (Page 436)

TI-83 Plus Inferential Statistics and Distributions 433
geometpdf(
geometpdf( computes a probability at x , the number of the trial on which
the first success occurs, for the discrete geometric distribution with the
specified probability of success
p . 0 
p
 1 must be true. x can be an
integer or a list of integers. The probability density function (pdf) is:

, 2 , 1 , ) 1 ( ) ( 1
= − = −
x p p x f x
geometpdf( p , x )
geometcdf(
geometcdf( computes a cumulative probability at x , the number of the trial
on which the first success occurs, for the discrete geometric distribution
with the specified probability of success
p . 0  p  1 must be true. x can be
a real number or a list of real numbers.
geometcdf( p , x )