DiscreteRatio [f,i]
gives the discrete ratio .
DiscreteRatio [f,{i,n}]
gives the multiple discrete ratio.
DiscreteRatio [f,{i,n,h}]
gives the multiple discrete ratio with step h.
DiscreteRatio [f,i,j,…]
computes the partial difference ratio with respect to i, j, ….
DiscreteRatio
DiscreteRatio [f,i]
gives the discrete ratio .
DiscreteRatio [f,{i,n}]
gives the multiple discrete ratio.
DiscreteRatio [f,{i,n,h}]
gives the multiple discrete ratio with step h.
DiscreteRatio [f,i,j,…]
computes the partial difference ratio with respect to i, j, ….
Details and Options
- DiscreteRatio [f,i] can be input as if. The character is entered dratio or as \[DiscreteRatio] . The variable i is entered as a subscript.
- All quantities that do not explicitly depend on the variables given are taken to have discrete ratio equal to one.
- A multiple discrete ratio is defined recursively in terms of lower discrete ratios.
- Discrete ratio is the inverse operator to indefinite product. »
- DiscreteRatio [f,…,Assumptions->assum] uses the assumptions assum in the course of computing discrete ratios.
Examples
open all close allBasic Examples (4)
Discrete ratio with respect to i:
Discrete ratio for a geometric progression corresponds to the ratio:
Enter using dratio, and subscripts using :
Discrete ratio is the inverse operator to Product :
Scope (20)
Basic Use (4)
Compute the discrete ratio:
The second discrete ratio:
Explicit shift structure in the function will typically be canceled:
Compute the discrete ratio of step h:
The second discrete ratio of step h:
Compute the partial discrete ratio:
Mix any orders:
Or any steps:
Special Sequences (14)
Polynomials have rational function ratios:
The root locations get shifted:
Rational functions have rational function ratios:
The root and pole locations get shifted:
Factorial functions have rational ratios including FactorialPower :
Binomial :
Exponential sequences have constant ratios:
The ratio of an exponential sequence corresponds to the DifferenceDelta of the exponent:
Hypergeometric terms are products of factorial, rational, and exponential functions:
Hypergeometric terms have rational ratios, so CatalanNumber is a hypergeometric term:
Q-polynomials (polynomials of exponentials) have q-rational ratios:
The roots are shifted in a geometric fashion:
Q-rational functions (rational functions of exponentials) have q-rational ratios:
The roots and poles are shifted in a geometric fashion:
Q-factorial functions have q-rational ratios including QPochhammer :
Q-hypergeometric terms are defined by having a q-rational discrete ratio:
Products of factorial functions have factorial ratios, including BarnesG :
Then the second ratio is rational:
Hyperfactorial is a product of ii:
A multivariate hypergeometric term is hypergeometric in each variable:
The binomial distribution is a multivariate hypergeometric term:
The difference of GammaRegularized with respect to n is a hypergeometric term:
This gives a simple expression for the ratio:
Similarly for BetaRegularized :
The difference for MarcumQ is expressed in terms of BesselI :
Special Operators (2)
DiscreteRatio is the inverse operator to Product :
Definite products:
Multivariate products:
Other special operators:
In this case the variable x is scoped:
Applications (6)
The defining property for a geometric sequence is that its DiscreteRatio is constant:
Solve a compound interest problem with interest rate 1+r:
DiscreteRatio gives the interest rate the compounding sequence:
The frequencies used in an even-tempered scale form a geometric progression with ratio :
Synthesize tones directly from frequencies:
Compare to a note scale:
Use the ratio test to verify convergence of a series whose general term is given by:
Compute the DiscreteRatio for this series:
The series converges since the limit at infinity of the ratio is less than 1:
Verify the result using SumConvergence :
Verify the answer for an indefinite product:
The DiscreteRatio of a product is equivalent to the factor:
Verify the solution from RSolve using a higher-step shift ratio:
Properties & Relations (6)
DiscreteRatio is the inverse for indefinite Product :
DiscreteRatio distributes over products and integer powers:
DiscreteRatio is closely related to DifferenceDelta :
DiscreteRatio can be expressed in terms of DifferenceDelta :
Use Ratios to compute ratios of adjacent terms:
Second-order ratios:
Ratios of step 2:
Use PowerRange to generate a list with constant ratio:
This is the sequence 2k with constant ratio:
Neat Examples (1)
Create a gallery of discrete ratios:
See Also
Ratios Product DifferenceDelta DiscreteShift DifferenceQuotient Pochhammer FactorialPower BarnesG Divide
Characters: \[DiscreteRatio]
Related Guides
History
Text
Wolfram Research (2008), DiscreteRatio, Wolfram Language function, https://reference.wolfram.com/language/ref/DiscreteRatio.html.
CMS
Wolfram Language. 2008. "DiscreteRatio." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/DiscreteRatio.html.
APA
Wolfram Language. (2008). DiscreteRatio. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/DiscreteRatio.html
BibTeX
@misc{reference.wolfram_2025_discreteratio, author="Wolfram Research", title="{DiscreteRatio}", year="2008", howpublished="\url{https://reference.wolfram.com/language/ref/DiscreteRatio.html}", note=[Accessed: 24-November-2025]}
BibLaTeX
@online{reference.wolfram_2025_discreteratio, organization={Wolfram Research}, title={DiscreteRatio}, year={2008}, url={https://reference.wolfram.com/language/ref/DiscreteRatio.html}, note=[Accessed: 24-November-2025]}