# Tag Info

1 vote
Accepted

### Analytical Solution in Generalized Heat Equation

just to add more to the comment, to help show why this is hard to solve analytically using separation of variables. To solve using separation of variables we must be able to find the eigenvalues of ...
• 127k
1 vote

### Intersection points of two-variable polynomials

Factoring shows they contain common factors. ...
• 57.3k
Accepted

We define: ...
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...
• 41k
Accepted

### Assume asymptotic value in a limit?

ClearAll[a, F, r, t, x] Use TagSet to define UpValues for ...
• 139k
Accepted

### Solving analytical integral

If you add assumptions that variables are positive, then ...
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### Series expansion using binomial theorem in Mathematica

You are almost there. Try the following: Series[(1 - (a/x))^(1/3), {a, 0, 2}] // Normal (* 1 - a^2/(9 x^2) - a/(3 x) *) Have fun!

### I can't solve this problem

Sum[Log[((k + 1)*(k + 3))/(k + 2)^2], {k, 1, Infinity}] yields -Log[3/2] or Log[2/3] or Log[2]-Log[3]. That is what Wolfram Mathematica and WolframAlpha do. Of ...
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...
• 139k
Accepted

### Calculate wavelet coefficients with Mathematica

The a step function from -1/2 to 1/2 may be declared as: rect[x_] = UnitStep[x + 1/2] - UnitStep[x - 1/2]; Plot[rect[x], {x, -1, 1}] And your step function f: <...
• 37.4k
1 vote

### Evaluate $\int_{0}^{\pi/2} \cos^a (x)\sin(bx) dx$ using Mathematica

This is getting too long to keep using comments. You need to use Limits for the special cases, then it works ...
• 127k
Accepted

### Is this a bug in IntegrateChangeVariables?

The wrong integral region is caused by failure of convergence of NMinValue. ...
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### Mathematica doesn't seem to be able to compute the Fourier transform of the Haar orthonormal basis over $L^2(\mathbb{R})$

Without loss of generality we may assume m==0 (see the translation property). Then in 13.2 on Windows 10 both ...
• 21k
1 vote

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1 vote

### Calculating an integral with a seemingly complicated integrand

At the first sight one can see that our integral depends on $u$ and $n$ and so we need not restrict them in advance but we should rather define our integral as a function of $u$ and $n$. Now we can ...
• 55.8k
1 vote

### How to find the difference equation from system response or primitive equation?

There is an undocumented internal function that does this. ...
• 8,517

### Why two the same integrals give different values?

Evaluating high-order polynomials is numerically unstable. Example: exact evaluation followed by numericalization is stable, Psi[7, 87] // N (* -0.0271578 *) ...
• 41k
1 vote

### Why earlier terms generated from AsymptoticDSolveValue change when increasing the order?

Inspired by the trick shown by Michael in the comment that when using using zero IC, spurious terms are gone, this is a function which will do this automatically. It only works with second order ode's ...
• 127k