# All Questions

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1answer
49 views

### How to solve this equation by Solve?

I have an equation to be solved. But Mathematica does not work for it. I hope the solution x can be expressed as a function of a and b ...
1answer
28 views

### Solving an equation involving a determinant (including spherical recursive functions)does not compute

I'm trying to solve this matrix to get a resulting function that depends on the variable Q (or if impossible, H3). When I try to to that I get two results: if I try to solve for Q, it doesn't show ...
1answer
54 views

### Finding all roots of a function within an interval [duplicate]

I have the following code: ...
1answer
88 views

### Solving two nonlinear equations in two unknowns

This is my code defining two nonlinear equations. I want to solve them simultaneously. ...
3answers
176 views

### Finding Root of BesselJ [closed]

When I work on some physical problem I needed to know how to get all of first 100 roots of BesselJ[n,x] function -which is a quasi periodic function-, as a List. I ...
2answers
83 views

### Maximising a function by finding roots of the derivative is too slow

I have the function r11[t,k] defined as follows ...
4answers
119 views

### Solving an equation involving elliptic integral

Consider the following function: f[θ_] = Integrate[1/(Cot[θ]^2 - Sin[θ]^2)^(1/2), θ]; Now, I want to determine the value of $\theta$ for which say $f(θ)=1$. I ...
1answer
319 views

### What replaces BesselJPrimeZeros[n, k] in current versions of Mathematica?

In older versions of Mathematica, there was a function called BesselJPrimeZeros used to find the zeros of the derivative of BesselJ function. http://mathworld....
0answers
86 views

1answer
64 views

### Plotting a variable that is within a hypergeometric function

I kindly ask for help with the following problem. I have two equations. The first one is: 1/(p (1 + (-1 + n) r)) == 1/Hypergeometric2F1[1, k - n, k, q/(-1 + q)] ...
1answer
157 views

### Hertzian contact mechanics: symbolically calculating the required force for a specific displacement

Consider two parallel Cylinders with Diameters of $R_1$ and $R_2$: The contact width can be calculated from 2D Hertz formula: $$a=2 \sqrt{\frac{PR}{\pi E_c}} \tag{1}$$ Where $P=\frac{F}{L}$ is ...
1answer
81 views

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0answers
71 views

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1answer
63 views

### Add more than one condition to my equation

I have the following code to solve for a bunch of n, m e U, but I need different conditions for n=0 and m=n, already explicit in my code, but I don't know how to make it work. I know I have to make it ...
0answers
51 views

### Solve and Special Functions [duplicate]

How can I use Solve to get the solutions of the following equation? Is it possible? ...
3answers
129 views

### Problem with C[i] of a second-order nonlinear ordinary differential equation

I'm trying to solve this differential equation (depending on the K0 parameter): ...
1answer
112 views

### Strange behavior of solution to $- \frac{\partial^2 \psi\left(x\right)}{\partial x^2} - e^{-\alpha x} \psi =0$

Say we have the following equation the following equation (inspired from quantum mechanics with $V\left(x\right) = - e^{- \alpha x}$): \begin{align} \label{eq:first-eq} - \frac{\partial^2 \psi\left(...
1answer
872 views

### How to solve a Sturm-Liouville problem with Mathematica (or, how to go from the complex to the general *real* solution)?

Let $a>0$ be a constant positive number. I am stuck trying to solve the following regular Sturm-Liouville problem: $$\frac{\mathrm d}{\mathrm d x}((a+x)f'(x)) = -v f(x),\qquad f(0)=f(1)=0$$ where ...
1answer
112 views

### Zeros of the Hankel function with complex parameter

I'm trying to find the zeros of the Hankel function (the first few will do) of the first kind $H^{(1)}_\nu(z) = J_\nu(z) + i Y_\nu(z)$ for complex argument $z$ but I'm not sure what is the best ...
3answers
639 views

### NSolve, no output

I want to eventually solve this with these three parameters being given from a list or table. It is not returning a solution, but I know that there is a 0 of this function (from looking at the plot) <...
2answers
349 views

### Backslide in NSolve in V11.1?

Bug introduced in 11.1.0 and persisting through 11.1.1 In V11.1, NSolve[BesselJ[0, x] == 0 && 0 < x < 20, x] returns no solutions: But in V11.0 (...
3answers
165 views

### Using the solution to an equation in another function

I am trying to use the solution to $R^2 \left(1-\frac{1}{r}\text{Erf}[r/4]\right)=r^2$ for $r$ in the function Potential$(R)=\frac{1}{R^2}\left(1-\frac{1}{r}\text{Erf}\left(r/4\right)\right)$ and ...
1answer
253 views

### Finding intersection points from contour plot

The Left hand side of the equation has only real part. But the right hand side has real and imaginary parts. So i am using a contour plot. The intersection of lefthand side and righthand side of ...
1answer
125 views

### The value of $\sqrt{\frac{\pi }{2}} C(1)$

I'm going through question 5 here, where they ask to approximate the integral $$I=\int_0^a \cos(t^2) \mathrm{d}t$$ with $a=\sqrt{\pi/2}$. This integral can be expressed using Fresnel integrals as ...
2answers
922 views

### Solving functional equation

Can I use Mathematica to solve a functional equation? For instance how to solve the following functional equation by using Mathematica? $$H(x+1)=xH(x)+\frac{1}{\Gamma(1-x)}$$ Solution is the ...
1answer
1k views

### Solving quintic in radicals

I need to find an explicit expression in radicals for the real root of the quintic equation ...
0answers
106 views

### Multiple Roots of Spheroidal Function

I am trying to compute multiple roots of a spheroidal Function (SpheroidalS1). At first, I define function RootsInRange which ...
1answer
131 views

### Solve equation which involves sum, binomial coefficient and erf

I want to solve the following equation. Unfortunately solve doesn't do the job. Is there any other way or am I doing something wrong? ...
2answers
115 views

### Help with solving trascendental equations involving Bessel's equations [duplicate]

I'm pretty new at using Mathematica, so I sometimes find errors in stuff so simple I can't seem to find where the error is. I've been trying to solve a trascendental equation that involves a number ...
0answers
91 views

### Spheroidal Eigenfrequency

I am trying to create a Mathematica function which will calculate the eigenfequencies of a spheroidal cavity. The expressions I use are based both on the book "Spheroidal Wave functions in ...
1answer
130 views

### A working command for solving a PolyLog equation? (Solve and NSolve don't work)

I need to solve an equation of this form: NSolve[a + x^b + PolyLog[c, x] + PolyLog[d, 1/x] == 0, x] Where $a, b, c, d$ are constants. For the sake of simplicity we can make $a = b = c = d$. Ok I ...
2answers
150 views

### Using FindRoot to track moving Bessel Functions zeros

Setting up the problem I want to study the common zeros of these two functions: ...
4answers
559 views

3answers
1k views

### Solve an equation that include Gamma

I want to solve the following equation Solve[Gamma[1 + x]/Gamma[x - 1/2] + 1 == 0, x] I have answer x=-0.25, but I can not obtain this answer with Mathematica. ...
1answer
319 views

### How to solve algebra equations containing integration and parameters?

I'm trying to solve two nonlinear algebra equations for two unknown parameters, U and Tf. Since some terms in these equations ...