# Questions tagged [wolfram-alpha]

For mathematical questions related to the usage of Wolfram Alpha.

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### What does meant notebook for wolfram demonstration? [closed]

I have got the below message from Elia Stiglier director of wolfram demonstration to make published paper online at wolfram demonstration, But really i don't understand what does meant notebook they ...
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### How does WolframAlpha solve quintic equations (5th degree polynomials)?

There exists no general formula for quintic equations. Then how does WolframAlpha solve quintic or higher degree polynomial. Is there a sure way to get values of roots of quintic or higher degree ...
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### How do I solve a recurrence relation with multiple conditions?

Suppose I have a recurrence relation like : $$f(n)=\begin{cases} 2*f(n-1) , & \text{n%2 = 1}.\\ f(n-1) + 1, & \text{n%2 = 0}. \end{cases}$$ \begin{...
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### What is $(-1)^X?$

Why the negative number raised to X gives strange graph? Y = (-1) / X This is sine and cosine both functions in real and imaginary part. How to explain this?
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### Is there some technique to plot complex functions by hand?

Is there some technique to plot complex functions by hand? Particularly, consider e.g. $$x=\exp(t)\cos(t), y=\exp(t)\sin(t)$$ This is equivalent to $e^x(\cos(y)+i\sin(y))$ along line $y=x$, just ...
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### Wrong Wolfram alpha result on $nth$ derivative?

I'm working with this function $$f(x)=\left(x+\sqrt{x^2-a}\right)^{-b}$$ and I would like to know the $nth$ derivative of $f(x)$. To this end, I ask Wolfram alpha about that given me the following ...
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### Why do these Residues and Numerically Calculated Contour Integrals Disagree?

I've been trying to numerically approximate various contour integrals of the function $f(z)=\frac{\sin\left(\pi x\right)}{\sin^2\left(\frac{15\pi}{x}\right)}$, but it seems that the residues and ...
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### Calculating an area of parametric function with wolframalpha?

Using wolframalpha, how can I calculate an area between some parametric function like: $\begin{cases} x(t) = t^2 - t \\ y(t) = t^3\end{cases}$ and: some other function like: $y = x^2$ ? I've ...
### How to find $\frac{146}7 \mod{7}$?
I understand that if $\gcd{(b,c)}=1$ then we can find $\frac{a}b\mod{c}$ by writing $$x\equiv \frac{a}b\mod{c}$$ $$bx\equiv a\mod{c}$$ then reducing $a$ and solving the modular equation by finding the ...