Mathematics Stack Exchange
Mathematics Stack Exchange

Questions tagged [wolfram-alpha]

For mathematical questions related to the usage of WolframAlpha.

WolframAlpha is an answer-engine developed by Wolfram Research that answers factual queries by directly computing the answer from structural data. Note that questions on how to use Mathematica should be asked on Mathematica Stack Exchange.

698 questions
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Why "is $f(x)$ an odd function?" does not work with this function?

We know that $f(x)$ is odd if $-f(x)=f(-x)$. The function is $$f(x)=\begin{cases}2x-1&\text{if $-2
manooooh
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Ability to generate a list of 3-digit numbers from a pool of digits in Wolfram?

I am attempting to generate a list of all possible 3-digit numbers that can be made by the numbers 1, 3, 5, 6, 7 and 9. I believe Wolfram should have the ability to give me a list, however, I am not too sure as to what to type. Can anyone help…
bio
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WolframAlpha, Solve for specific values of Z

Question I have the following command I am entering: solve[y=prime(x-1)+(z)/prime(x-1)+1, z=28] over the integers I would like to be able to say: Solve for z=28,29,30 or 31 . Is there any way to do that? I tried the following, but it…
Menelaos
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How to find multifactorials $ n\underbrace{!!\ldots !}_m$ in Wolframalpha?

I heed to compute $ n\underbrace{!!\ldots !}_m$. The formula is $ n\underbrace{!!\ldots !}_m = \prod_{i=1}^{k}(mi-r)$, $n=3m-r$, $k \in Z$, $r \in \{0,1,\ldots, m-1\}$. Question. Is it exist a short formula in Wolframalpha to find, for example,…
Nick
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How to convert a formula to discrete values in wolfram-alpha?

I don't know where this question fits, whether it is the right place... I plotted the Logistic Function $y=\frac{0.8}{1 + e^{-(x-6)}}$ using wolframalpha, here. Now I want to make it discrete, so I can copy it to excel and make a plot. I want to…
Tar
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Creating an arithmetic sequence that increases by a number other than 1 in Wolfram|Alpha

Say I want to find numbers between 1 and 10, but I want the sequence to increase by .1, how would I accomplish this?
user406613
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change output format of partial fraction decomposition

If I ask Wolfram the Partial Fraction Decomposition of, for example, $$\frac{z^3}{(1-z-z^2)(1-z)(1-2z)}$$ The answer is $$\frac{z}{z^2 + z - 1} + \frac{2}{z^2 + z - 1} - \frac{1}{z - 1} - \frac{1}{2z - 1}$$ My question is what do I have to type to…
ddz
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What does "rational approximation" in Wolfram Alpha mean?

I'm trying to figure out a nicer rational expression of the following: $$\frac{1}{14.5}$$ http://www.wolframalpha.com/input/?i=1%2F14.5 But Wolfram Alpha only gives "rational approximation" $\frac{2}{29}$. Is this the exact analytic expression or is…
mavavilj
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True or false under several conditions

I want to check whether $$\max\bigl(0, x+\max(0, y+z-1)-1\bigr)=\max\bigl(0, z+\max(0, x+y-1)-1\bigr)$$ under restriction $x,y,z\in[0,1]$ but I don't know how to type it in WolframAlpha. For example this expression does not work: max(0, x+max(0,…
Bogdan
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PrimeQ[ Table[sum_(n=1)^(N)n!, {N,1,30}]]

The PrimeQ[Table[...]] command used to work in Wolfram|Alpha back in 2012 but now it doesn't give any answer. Is there a substitute?
Brian
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About a solution in Wolfram Alpha

I'm intrigued by this finding on the extraordinary portal WolphramAlpha. What is the reason why the solution has not been simplified, eliminating the factor $\frac{\sqrt x \sqrt{x+2}}{\sqrt {x(x+2)}} $? If not removal is justified, I would love to…
Piquito
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Plotting standard deviation function using WolframAlpha

I'm trying to plot a standard deviation function using WolframAlpha's function plotter and my function looks like this: $SD(Y) = \sqrt{\sum_{i=2}^{k}\frac{k(i-1)}{ (k-(i-1))^2 }}$ where k goes from 1 to 50. And I've written my function like this in…
Nubcake
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Wolfram Alpha can plot an equation but not solve it

I'm trying to solve the equation $24.6347 \left(246.347 x + \sqrt{(246.347 x + 20)^2 + 1} + 20\right)^{-a} =\\ 30.2879 \left(-33.6532 x + \sqrt{x (1132.54 x - 20191.9) + 90001} + 300\right)^{-a}$ for $a>0$ but Wolfram Alpha doesn't give me a…
Paul Ostmann
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Why does WolframAlpha give different answers for these two equivalent limits?

Here are two limits with different answers provided by Wolfram|Alpha: Limit 1: $$\lim_{z\to \frac{2}{5}-\frac{i}{5}} \frac{2\left(z-\frac{2-i}{5}\right)}{(1-2i)z^2+(6i)z+(-2i-1)}=-\frac{i}{2}$$ Limit 2: $$\lim_{z\to \frac{2}{5}-\frac{i}{5}}…
Alex.F
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How calculate one side limit with WolframAlpha?

I read examples, and try: lim ln(x+1) as x->inf from the left but always wolfram alpha represent infinity as positive.
Dmitry
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