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Questions tagged [equation-solving]

763 questions
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How to solve simultaneous non-linear equations with exponential functions?

I have a system of equations to solve for x1 and x2: 2*erf(A*x2)*exp(B*x1^2+C*x2^2)-D*erf(x1)=0 2*erf(D*x2)*exp(E*x1^2+F*x2^2)-G*erf(x1)-erf(H*x2)*exp(I*x1^2)=0 where B and C are negative while rest of the constants are positive. I tried to solve…
Deepak
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What are the best libraries or software to numerically solve a nonlinear system?

I have a system of 8 polynomial equations of 7th grade eight in 8 variables with constraints (minimum and maximum acceptable values​​). In your experience and knowledge of what is the most efficient "package" to attack this kind of…
psmith
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How to solve symbolic equation in matlab

I have an equation in Matlab according to X parameter . I want to find the amount of X for the random amounts of F(x) . and I tried the code below . but It gives me two different results while my equation should have just one result . even I tried…
Bahareh LV
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C++ solving for quartic roots (fourth order polynomial)

As part of my project I need to solve a quartic polynomial in a closed form in C++. A*x4 + B*x3 + C*x2 + D*x + E = 0 I found several links to this end. One of them is here. But it computes all roots, while I want just real roots. The algorithms…
batista cori
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Solving equations in C

I need to solve the following equation in C: a + ln(a) = x I know the value of x and I need to find the value of 'a' that satisfies this equation. Can anyone suggest an efficient method for solving this equation. May be Newton Raphson, or anything…
Ashwin
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Solve system of polynomials (4, second order) in C

I'm trying to solve a system of 4 second order polynomial equations using C++. What is the fastest method for solving the system, and if possible, could you link or write a little pseudocode to explain it? I'm aware of solutions involving a…
smörkex
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Matlab: how to solve a binary system of equations?

I'm trying to solve a system of equation with the following form: a5 + a6 + a7 + f5 + f6 + f7 = 11; b5 + b6 + b7 + e5 + e6 + e7 = 100; c5 + c6 + c7 + d5 + d6 + d7 = 100; a5 + b5 + c5 + d5 + e5 + f5 = 11; a6 + b6 + c6 + d6 + e6 + f6 = 100; a7 + b7 +…
Samsky
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Matlab Solve System of Equations with Quantized Variables

I am trying to use solve() to solve a system of equations of the following form eq1=a1x+a2y; eq2=b1x+b2y; where a1 = .05 for values of x<5, .1 for values of 5 Is there a way to solve for this using solve? As in sol = solve(eq1,eq2);
user1265868
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solutions for factor levels when using linear models in R

I am running linear models to look at the significance of independent factors involved. The example model is: ` mymod1 <- lm(temp ~ bgrp+psex+tb,data=mydat) summary(mymod1)` I look at the summary to check out the significance of each…
baz
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Python semiprime factorization equation solver issues

I am a farmer / novice number theory researcher. I happened to discover some years back a pattern that emerged in the distribution of the prime numbers that related the number of primes to the operation of 300 Fibonacci-like sequences. Well, as a…
J. W. Helkenberg
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Calculating 4th power differences

I am using Modelica for solving a system of equations for heat transfer problems, and one of them is radiation which is written as Ta^4-Tb^4 Can someone say if it is computationally faster solving a system with the equation written…
ruben baetens
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Why does sympy struggle with solving lists of equations vs a single equation call?

I have the following minimal example: import sympy as sp eq = sp.S("-p**2*(3*p**2 - 9*p + 7)/(p**2 - 3*p + 3) + q") # This eventually terminates after a few seconds sp.solve(eq, dict=True) # Result: [{q: p**2*(3*p**2 - 9*p + 7)/(p**2 - 3*p +…
WaveL
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Solve linear system in R

I have a system of 3 equations : g + v_1 = 8 +1/2 *v_1 +1/4 *v_2 + 1/4 *v_3 g + v_2 = 16 +1/2 *v_1 +0 *v_2 + 1/2 *v_3 g + v_3 = 7 +1/4 *v_1 +1/4 *v_2 + 1/2 *v_3 Setting v_3 = 0 one can obtain v_1=1.33,v_2 =7.47,v_3=0,g=9.2. How can I solve this…
Homer Jay Simpson
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How to use Sympy solve for a timeseries

How can I run sympy Solve for timeseries? Lets say I want to Solve for X in the following equation (1+df['LTEPSG']) * df['TTMEPS']-X=0 and I want my solution for X to be a timeseries. Dates LTEPSG TTMEPS 2022-09-01 0.13434 219.603…
user20856754
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How to allocate a product using R

I want to solve the following problem using R, and I am struggling to find a good way to do so. I have a sales forecasts for two products (Product 1 & Product 2), of which there are 2 variations each (A & B). dat_forecast <- data.frame( product =…
Johnny
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