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System of ODEs Solver

Solves 2×2 and 3×3 linear systems x′ = Ax with eigenvalues, eigenvectors and the closed-form general solution, classifies the fixed point (node, spiral, centre, saddle, degenerate), and integrates arbitrary nonlinear 2D systems numerically with a phase portrait.

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Open System of ODEs Solver and you get an answer straight away, with no account to create. It covers node, spiral, centre, saddle, degenerate — adjust any of them and the result follows immediately.

How to use it

  1. Open the tool — no signup or install needed.
  2. Enter your input or adjust the available options.
  3. Get your result instantly, then copy or download it.

Frequently asked questions

What does System of ODEs Solver do?

Solves 2×2 and 3×3 linear systems x′ = Ax with eigenvalues, eigenvectors and the closed-form general solution, classifies the fixed point (node, spiral, centre, saddle, degenerate), and integrates arbitrary nonlinear 2D systems numerically with a phase portrait.

What does it take into account?

It factors in node, spiral, centre, saddle, degenerate. Change any of them and the output follows immediately.

When would I actually use this?

Checking a derivative or an integral you worked out by hand, finding where a function turns, and getting a numeric answer when no closed form exists.

What is the most common mistake?

Integrating across a discontinuity as if it were not there. A numeric method will happily return a finite value for an integral that diverges — check the domain before trusting the number.

How is System of ODEs Solver different from System of Linear Equations Solver?

They sit next to each other but answer different questions. System of Linear Equations Solver: solve 2×2, 3×3 and 4×4 linear systems by Gaussian elimination, Cramer's rule or the matrix inverse — with the determinant, step-by-step working, and detection of no-solution and infinite-solution cases. Pick whichever matches what you're starting from — both are free.

Is there a tool for the next step?

System of Nonlinear Equations Solver is the closest one after this: Solve 2- or 3-variable nonlinear systems (polynomial, trigonometric, exponential) with multivariate Newton's method — enter equations as text, set a starting guess, and surface every real solution with its residual.

What else is worth having open alongside it?

Bernoulli ODE Solver and First-Order ODE Solver — they come up in the same task often enough to be worth a second tab.

Where do the figures come from?

Symbolic results are exact; numeric ones come from adaptive quadrature or a standard step method, and the tool reports which. Where both are available, compare them — a large gap means the problem is ill-conditioned.

Further reading

All guides →
ExplainerThe Expected Value Is a Number That Never HappensOutcomes of 10, 20 and −5 with probabilities 0.5, 0.3 and 0.2 give an expected value of 10. Shift the probabilities slightly and it becomes 10.5 — a result none of the three outcomes can produce.ExplainerAn Error Bar That Shrinks Is Not the Standard DeviationFor 10, 12, 15, 11, 13, 14 the standard deviation is 1.87 and the standard error is 0.76. They answer different questions, and only one of them gets smaller as you collect more data.ExplainerAn r of 0.85 That Proves NothingFive points give r = 0.853, which sounds strong. The threshold for significance at five points is 0.878, so this one falls short — and a perfect parabola scores exactly zero.ExplainerQuadruple the Sample to Halve the IntervalA mean of 100 with a standard deviation of 15 over 30 observations gives 100 ± 5.37 at 95 %. Going to 120 observations gives ± 2.68 — exactly half, because the sample size enters under a square root.ExplainerThe Same Three Temperatures Give Three Different Coefficients of VariationFor 2, 4, 4, 4, 5, 5, 7, 9 the coefficient of variation is 42.76 %. It is the right tool for comparing spread across different scales — and completely wrong for any scale whose zero was chosen by convention.ExplainerThree Dice Cluster, and One Die Does Not3d6 and 1d20 have almost the same average and nothing else in common. Against a target of 12 the three dice are better, against 18 they are five times worse — and the calculator gives the exact figures rather than a simulation.