Tagged Questions

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

956 views

Finding all possible solutions to a math mind game

In the example below the letters shall be replaced by numbers. The numbers are from 1 to 9, and each letter has the same number (...
62 views

Gram Schmidt Process for functions [duplicate]

I want to implement the Gram Schimdt procedure to the space of functions in the following form \begin{align}‎ ‎R(y,x)=\left\{‎ ‎\begin{array}{ll}‎ f(x,y), ‎& y\leq x\\ \\‎ g(x,y), ‎& y>x‎ ‎\...
252 views

Law of Cosines to determine angle change along spiral

The Spiral I'm trying to place circles along the outside of an Archimedean spiral. Shown below: ...
165 views

Is there a giant AND symbol/How to solve tons of equations simultaneously

$$\sum_{k=1}^na_k=a_1+...+a_n$$ $$\prod_{k=1}^na_k=a_1\cdot...\cdot a_n$$ $$\large{?}\small{_{k=1}^na_k=a_1~\&\&...\&\& ~a_n}$$ What in mathematica would allow me to index logical ...
2k views

Solving a polynomial equation with a condition of equality on roots

Let the following equation have two equal roots: f[x_] := x^3 - p x^2 + q x - r And I want to find out what the three roots are. Not knowing how to put this ...
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How can I simulate this toggle mechanism?

I've been introduced to Mathematica very recently. Basically, I haven't actually "solved" anything in my Mathematica lifetime, but I've done some simulations. With my fractional knowledge, I tried ...
907 views

Methods for NSolve

I've been using NSolve a moderate (50-100 equations) size system of linear equations and it has been working splendidly (Solve ...
414 views

Tweaking Solve for systems of polynomial equations

I am trying to solve the following system of $6$ quadratic equations in $6$ variables: ...
371 views

How to solve an equation with two variables in Mathematica

If I solved an example equation like |x|+|y|=1 numerically, I would to get a 90° rotated rectangle. If I was to plot the equation, it would result in an image like ...
91 views

Have transformation rules to be explicitly set?

I think this problem is not the hardest one, but I can't hit on it. I want to NSolve an equation. For this equation I use a transformation rule "ampTimes". First I used it like this: ...
248 views

Eliminate variables by dividing two equations

how is it possible to divide two equations with Mathematica? I have the following code: ...
2k views

Error entering equation in DSolve

I entered a command incorrectly as follows: DSolve[{y'[x]=y[x]},y[x],x] I am now experiencing: ...
460 views

Unable to solve a set of equations with Solve

I'm trying to solve the following equation using Mathematica 9.0.1.0 : ...
996 views

How to write a variable in terms of the other [duplicate]

I have an equation that defines a variable like y=4x+a. I had another equation, z=x+2+4, I would like to know if there is a way in Mathematica to get an expression in which z= a*y+C, in which a and C ...
235 views

Simplify equation using conditions/inequalities

If I have an equation like f[x](1 + a)==0 I'd like to be able to tell Mathematica that 1+a doesn't vanish in general, and get back ...
138 views

Partial products in prime steps [duplicate]

I am trying to find out partial products going up in prime steps for Euler's product formula $$\prod_{p} \frac{1}{1-p^{-s}}$$ Trying things like ...
258 views

Find the centre of FindGeometricTransform

I'm interested in using Solve[] to find the centre point of rotation (as an $x,y,z$ coordinate point) and axis of rotation (as a vector) from a ...
80 views

Solving polynomial equations takes infinit time

I need to solve an polynimial equation, but when i try to use Solve or NSolve in mathematica, its cant find the solution in appropriate time (i interrupted calculation after 5 hour left). The ...
233 views

Solving algebraic equations

How may I make n and k in terms of x and y in this ...
222 views

Reduce with Integer domain, but receive a rational solution

Bug introduced in 6.0 and fixed in 10.0 I want to find the integer values $k$ so that D[f[x], x] has integer solutions. I tried ...
236 views

Reduce Cannot Solve Complicated Function

As per the answer to this question: SolveAlways rejects inequality, I tried the following commands: ...
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SolveAlways rejects inequality

I have two functions of x, f and g. f[x] = g[x] + 2, ...
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Plot a table of ranges

I have table with values like: t = {1.234 <= a <= 2.345, 3.42 <= a <= 5.67, ...} and I want to plot this table, the ...
192 views

Solve-ing with initially unassigned parameters and Solve-ing using their numerical values produces different results

I am trying to solve an equation using the following piece of code: ...
572 views

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Reduce[] giving incorrect result for equation over $\mathbb{Z}^4$

This is partially in response to a question I posted earlier, although the problem in this case appears to be distinct from the problem there, so I am temporarily filing this as a separate question. ...
1k views

Solve[] unexpectedly giving empty solution sets for extremely large problems

I was calculating the set of lattice vectors in $\mathbb{Z}^4$ which have taxicab norm $r$. For example, executing ...
160 views

I got wrong answers when solving an equation

I have this expression: ...
213 views

Faster Solve for Fermat 4n+1 conjecture

Assuming that Fermat 4n+1 conjecture (each prime of the form 4n+1 is the sum of two squares) is true then I like to solve the ...
I would like to 'decompose' a diagonal positive real matrix $E$ of rank $D$ onto $\sum_{i=1}^{D}c(i)N^i$: $$E = \left( \begin{array}{ccc} 0 & & & \\ & a & & \\ &... 1answer 312 views How to enter and solve this equation in finite fields? Is there a way in Mathematica 9 to enter and solve the following equation p(x) = r^x where p(x) is a polynomial whose coefficients are drawn from a finite field, and r is a primitive root of ... 2answers 196 views Quadratic Equations \bmod p^k As part of a larger program, I need to solve A x^2+B x+C \equiv 0 \pmod {p^k} for prime p. Right now I'm doing this by calling ... 0answers 349 views No response from DSolve Using optimal control theory, I am trying to find the optimal paths of d and k such that they will maximize profit as given by lc: ... 1answer 278 views Perform FindRoots on Function Evaluation Containing RootSearch I am using Ted Ersek's RootSearch function in Mathematica 9.0 (http://library.wolfram.com/infocenter/Demos/4482/) to create a function that I am using for graphing. ... 3answers 653 views Extracting coefficients from g=a*x+b*y+c*x*y I have a Response Surface Equation (RSE) that I'm trying to extract coefficients from. It has a form similar to: g = a*x + b*y + c*x*y; I want to be able to ... 1answer 193 views Problem to solve an integral equation [closed] I am new to Mathematica. I am trying to numerically solve for C in the following equation:  \begin{array}{lcl} -\int_0^\infty (5000000+100000 x+ C)^{-1} ... 1answer 284 views Solving Complex Equation Over Reals I want to solve the equation \frac{abi}{a+bi}=4-2i, where a and b are real numbers. I know from hand-solving the answer is a=5, b=-10. How do I get Mathematica to tell me this? I tried: <... 1answer 593 views Resonance Curve using NDSolve I am trying to make a resonance curve like this one below, using NDSolve. I tried to use code as below. Basically I try to hold solution for a w (driving frequency value) using NumericQ and then ... 1answer 100 views Failure message from Reduce I am getting the message Reduce::nsmet: This system cannot be solved with the methods available to Reduce. while trying to solve the following equation: ... 1answer 315 views Calculate max value Update Using ... 0answers 43 views Store results of inequality [duplicate] I eveluated some values using Reduce commend and I store them in a Table ... 1answer 219 views Solving problems with the floor function I've got the following problem: If I want to calculate the following equation, ... 2answers 212 views Plotting double inequality only for integer values RegionPlot is plotting for all values. And using ListPlot I can only evaluate one inequality. How can I plot this type of ... 3answers 961 views Solve the system of equalities and inequalities I have a system of expressions, in which each expression is an equality or inequality expression of the following form: Var = Var1 + Var2 Var \odot number Var \odot Var1 \odot = \leq | \geq | ... 3answers 153 views Discrete inequality plotting I have an equation like this:$${20 \choose k}\cdot \sum_{i=0}^k {k \choose i}\cdot i \leq 1+f. I want to plot this inequality as the dependency between k and <...
I have a table for example: t = Table[k,{k,5}] which returns {1,2,3,4,5} and for every element in this table I want to check when it is $\leq 1 + a$. I ...