# Tagged Questions

Questions on the analytic and numeric equation solving functions of Mathematica (Solve, Reduce, NSolve, FindRoot, DSolve, RSolve, etc.).

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### Find all solutions which satisfy the given conditions

Let $$m=9n^3+30n^2-9n$$ where $n \in \mathbb{Q^{+}}$ and $m \in \mathbb{Z}$ . Find all solutions which satisfy the given conditions. So I've tried to solve this manually and I was able ...
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### Wrong root when using numerical values

I have the following inequality: $$\sqrt{\frac{a}{2x}}+ \frac{b}{1-\frac{a}{a+\sqrt{a(2bx + a)}}} + \frac{a}{2x\frac{a}{a+\sqrt{a(2bx + a)}}\left(1-\frac{a}{a+\sqrt{a(2bx + a)}}\right)} < f$$ on ...
453 views

### Solving an equation involving an integral

How do I get the following into Mathematica, solving for $a$: $$0.7 = 1 - \frac{2}{a} \times \left[ \frac{1}{a} \int_0^a \frac{x}{\exp(x)-1}\mathrm dx + \frac{a}{6} - 1\right]$$
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### Improving strategy to solve this constrained root-finding problem

I am looking for roots of the function eqs defined below. It has $2k$ unknowns and returns a vector of $2k-1$ components. The sole purpose of the following block ...
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### Solve involving simple cancellation on both sides fails when there are too many constants

I've been working with a number of equations of the form x = A * B * x ^ C where I need to solve for x--basically, equations ...
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### Nonrectangular tensor encountered [closed]

I am trying to solve a system of equations which characteristic matrix: ...
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### Probleme with Ted Ersek's RootSearch package [duplicate]

The following question is a logical continuation of this one. The Ted Ersek's RootSearch package doesn't work with this code: ...
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### Manipulation linear systems of equations

I have the following system of equations: i1 = ix - β*ib; i2 = (β + 1)*ib; i3 = ix + ib; vx = i1*Rc + i3*Rb; v1 = i2*Rϵ + i3*Rb; v1 = -ib*rπ; I tried using: <...
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### Solving this system of nonlinear equations

Edit Interestingly, I realized solving my problem with $2n$ equations appeared to be more efficient than using mathematical results on the solutions to reduce the problem to $n$ equations (the $n$ ...
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### Assigning solutions to a variable [duplicate]

If I do Solve[x+1==0, x] then I get {{x -> -1}} But I want to assign the solution -1 directly before seeing the result, ...