f(x) GraphLab 3D 2D/3D Graphing Studio, Step-by-Step Matrix & Symbolic Calculus Workbench العربية

Complete Interactive Mathematical Functions, Surfaces & Solvers Directory

Filter instantaneously across 92 pre-configured mathematical workbenches ready to launch with live formulas and pre-solved invariants.

1. 2D Cartesian, Polar & Parametric Curves (24)

Physics & Vibrations
Damped Harmonic Oscillator y = e^(−ax)·cos(bx) — Envelope & Phase Decay

Models underdamped mechanical springs and RLC circuits where exponential envelope e^(−ax) bounds rapid cosine oscillations.

y = exp(-a*x)*cos(b*x)
Probability & Statistics
Gaussian Normal Bell Curve f(x) = (1 / σ√2π)·e^(−(x−μ)²/2σ²)

Normalized probability density function with total area equal to 1, peak at x = μ, and inflection points at x = μ ± σ.

y = exp(-(x - c)^2 / (2*a^2)) / (a*sqrt(2*pi))
Machine Learning & Biology
Logistic Sigmoid Curve S(x) = L / (1 + e^(−k(x − x₀)))

Bounded S-shaped activation and population carrying-capacity curve with inflection symmetry at y = L/2.

y = a / (1 + exp(-b*(x - c)))
Signal Processing & Optics
Normalized Sinc Function sin(ax)/(ax) & Fraunhofer Diffraction Intensity

Ideal low-pass Nyquist reconstruction kernel in DSP; its square sinc²(x) governs single-slit optical diffraction fringes.

y = sinc(a*x)
Classical Algebraic Curves
Witch of Agnesi y = 8a³ / (x² + 4a²) — Cauchy-Lorentz Resonance Profile

Rational bell curve studied by Maria Gaetana Agnesi (1748), identical in form to spectral Lorentzian line shapes and Cauchy distributions.

y = 8*a^3 / (x^2 + 4*a^2)
Structural Mechanics
Catenary Arch y = a·cosh(x/a) vs. Parabolic Approximation

Exact equilibrium shape of a uniform flexible cable hanging under gravity, compared side-by-side against its osculating parabola.

y = a*cosh(x/a)
Precalculus & Asymptotes
Rational Function f(x) = (x² − 4)/(x² − 1) — Vertical & Horizontal Asymptotes

Demonstrates exact pole branch splitting at x = ±1, roots at x = ±2, y-intercept at (0, 4), and horizontal asymptote y = 1.

y = (x^2 - 4) / (x^2 - 1)
Differential Calculus
Depressed Cubic f(x) = x³ − 3ax + c & Parabolic Derivative f′(x)

Visualizes how local maximum at x = −√a and minimum at x = +√a align directly with the roots of f′(x) = 3x² − 3a.

y = x^3 - 3*a*x + c
Acoustics & Wave Superposition
Acoustic Beat Interference cos(ω₁x) + cos(ω₂x) & Modulation Envelope

Superposition of two close frequencies produces rapid carrier waves modulated by slow beat envelope 2·cos(Δω·x/2).

y = cos(a*x) + cos(b*x)
Approximation Theory
Chebyshev Polynomial T₅(x) = 16x⁵ − 20x³ + 5x — Equioscillation Property

Minimax polynomial on [−1, 1] exhibiting six alternating ±1 extrema that suppress Runge’s phenomenon in polynomial interpolation.

y = 16*x^5 - 20*x^3 + 5*x
Chemical Physics
Lennard–Jones 12-6 Potential V(r) = 4ε[(σ/r)¹² − (σ/r)⁶]

Balances Pauli short-range r⁻¹² repulsion against London dispersion r⁻⁶ attraction with equilibrium minimum at r = 2^(1/6)σ.

y = 4*a*((1/x)^12 - (1/x)^6)
Deep Learning Architectures
Swish x·σ(βx) vs. GELU Activation Functions in Transformer Networks

Compares smooth non-monotonic neural network activations that eliminate ReLU dead-neuron gradients.

y = x / (1 + exp(-a*x))
Real Analysis & Non-Differentiability
Modulus Fold |x² − a²| − b & Fractional Power Cusp x^(2/3)

Illustrates continuous curves with sharp corner points and vertical-tangent cusps where classical derivatives fail to exist.

y = abs(x^2 - a^2) - b
Special Functions
Euler Gamma Function Γ(x) & Gaussian Error Function erf(x)

Plots analytic continuation of factorials Γ(n) = (n−1)! across negative poles alongside bounded integral erf(x).

y = gamma(x)
Polar Coordinates
Polar Rhodonea Rose Curve r(θ) = a·cos(kθ) — Petal Symmetry Rules

Generates k petals when k is odd and 2k petals when k is even; tune slider b live to watch petal topology transform.

r = a*cos(b*theta)
Polar Coordinates
Limaçon of Pascal & Cardioid r(θ) = a + b·cos(θ) — Inner Loop Geometry

Transitions smoothly from convex dimpled limaçon (a > b) to cusp cardioid (a = b) and inner-loop limaçon (a < b).

r = a + b*cos(theta)
Polar Coordinates
Archimedean Spiral r(θ) = a + bθ — Constant Turn Spacing

Successive turns maintain constant radial separation Δr = 2πb, used in scroll compressors, watch springs, and antenna arrays.

r = a + b*theta
Transcendental Polar Curves
Temple Fay’s Transcendental Butterfly Curve in Polar Coordinates

Famous 1989 transcendental polar curve combining exponential, harmonic 4θ, and subharmonic sin⁵((2θ−π)/24) wing modulation.

r = exp(sin(theta)) - 2*cos(4*theta) + sin((2*theta - pi)/24)^5
Orbital Mechanics & Conics
Keplerian Conic Orbit r(θ) = p / (1 − e·cos θ) — Focus at Origin

Unified polar equation of planetary orbits with focus at the pole: circle (e=0), ellipse (0<e<1), parabola (e=1), hyperbola (e>1).

r = a / (1 - b*cos(theta))
Parametric Oscillations
Lissajous Harmonic Figure x(t) = A·sin(at + δ), y(t) = B·sin(bt)

Orthogonal harmonic oscillations used on laboratory oscilloscopes to measure frequency ratios a:b and phase difference δ.

(4*sin(a*t + c), 3*sin(b*t))
Kinematic Roulette Curves
Astroid Four-Cusped Hypocycloid x(t) = a·cos³(t), y(t) = a·sin³(t)

Locus of a point on a circle of radius a/4 rolling inside a fixed circle of radius a; satisfies x^(2/3) + y^(2/3) = a^(2/3).

(a*cos(t)^3, a*sin(t)^3)
Mechanical Gear Profiles
Epicycloid Gear Tooth Curve x(t) = (k+1)cos t − cos((k+1)t)

Generated by rolling a unit circle around the outside of a circle of radius k, foundational to cycloidal gear tooth geometry.

((a + 1)*cos(t) - cos((a + 1)*t), (a + 1)*sin(t) - sin((a + 1)*t))
Calculus of Variations
Cycloid & Brachistochrone Curve x(t) = r(t − sin t), y(t) = r(1 − cos t)

Bernoulli’s curve of fastest descent under uniform gravity and Huygens’ tautochrone pendulum path.

(a*(t - sin(t)), a*(1 - cos(t)))
Self-Similar Geometry
Equiangular Logarithmic Spiral x(t) = a·e^(bt)cos t, y(t) = a·e^(bt)sin t

Jakob Bernoulli’s self-similar spiral cutting all radial rays at constant angle cot⁻¹(b), observed in nautilus shells and spiral galaxies.

(a*exp(b*t)*cos(t), a*exp(b*t)*sin(t))

2. 3D Surfaces & Optimization Landscapes (20)

Quadric Surfaces
Hyperbolic Paraboloid Saddle Surface z = a(x² − y²) & Minimax Point

Doubly-ruled negative Gaussian curvature surface curving upward along x and downward along y with canonical saddle point at (0,0,0).

z = 0.35*(x^2 - y^2)
Wave Optics & radially Symmetric Fields
3D Radial Sinc Sombrero Surface z = A·sin(kr)/(kr)

Axisymmetric 2D Fourier transform of a circular aperture, displaying central Airy-like peak surrounded by concentric annular ripples.

z = 3.2*sinc(1.8*sqrt(x^2 + y^2))
Quadric Surfaces & Convexity
Elliptic Paraboloid Convex Bowl z = ax² + by² — Elliptical Level Curves

Strictly convex quadratic surface with positive definite Hessian H = diag(2a, 2b) and nested elliptical contour isolines.

z = 0.28*(x^2 + 1.5*y^2) - 2
Differential Geometry
Monkey Saddle Surface z = x³ − 3xy² — Degenerate Zero-Hessian Point

Real part of complex cubic Re(z³) possessing three alternating valleys and ridges where both gradient ∇f and Hessian vanish at (0,0).

z = 0.16*(x^3 - 3*x*y^2)
Non-Convex Optimization
Himmelblau’s Optimization Benchmark f(x,y) = (x²+y−11)² + (x+y²−7)²

Multi-modal optimization test landscape featuring one central local maximum and four distinct global minima equal to zero.

z = 0.025*((x^2 + y - 11)^2 + (x + y^2 - 7)^2) - 2.5
Gradient Descent Benchmarks
Rosenbrock’s Banana Valley f(x,y) = (1 − x)² + b(y − x²)²

Narrow parabolic valley where finding the valley floor is easy, but converging to the global minimum at (1, 1) challenges first-order optimizers.

z = 0.015*((1 - x)^2 + 30*(y - x^2)^2) - 1.5
Electrostatics & Vector Calculus
Gaussian Dipole Field z = A·x·e^(−α(x² + y²)) — Paired Source & Sink

Antisymmetric smooth scalar potential exhibiting paired global maximum and minimum separated across the nodal line x = 0.

z = 3.5*x*exp(-0.45*(x^2 + y^2))
2D Acoustic Cavities & PDEs
2D Membrane Standing Wave Mode z = A·sin(kₓx)·cos(kᵧy)

Eigenfunction solution of the 2D Helmholtz wave equation on a rectangular drumhead with orthogonal nodal grid lines.

z = 2.2*sin(1.2*x)*cos(1.2*y)
Image Processing & Wavelets
2D Laplacian-of-Gaussian (Mexican Hat / Ricker Wavelet) Filter

Negative normalized Laplacian of a 2D Gaussian kernel used across computer vision and seismology for multi-scale edge detection.

z = 3.2*(1 - 0.45*(x^2 + y^2))*exp(-0.22*(x^2 + y^2))
Global Metaheuristics
Rastrigin Multi-Modal Optimization Landscape — Local Minima Lattice

Parabolic bowl superposed with periodic cosine lattice creating dozens of deceptive local minima trapping greedy solvers.

z = 0.18*(20 + (x^2 - 10*cos(2*pi*x*0.5)) + (y^2 - 10*cos(2*pi*y*0.5))) - 3
Conic Sections & Relativity
Circular Cone Surface z = √(x² + y²) — Constant Unit Gradient |∇z| = 1

Conical surface smooth everywhere except the apex singularity (0,0), exhibiting perfectly concentric equidistant circular contours.

z = sqrt(x^2 + y^2)
Spherical Geometry
Spherical Dome z = √(R² − x² − y²) — Constant Positive Curvature 1/R²

Upper hemisphere of radius R = 3 demonstrating normal vector alignment along position vector (x, y, z) and steep equatorial rim.

z = sqrt(max(0, 9 - x^2 - y^2))
2D Potential Theory & Electrostatics
2D Logarithmic Potential Funnel z = k·ln(x² + y² + ε) — Harmonic Green’s Function

Fundamental Green’s function of the 2D Laplace equation Δu = 0 governing line-charge electrostatics and ideal fluid sources.

z = 1.2*ln(x^2 + y^2 + 0.15)
Minimal Surfaces & Complex Phase
Phase Ramp & Riemann Branch Cut z = c·atan2(y, x)

Visualizes complex argument arg(x + iy) spiraling smoothly around the origin up to its branch-cut jump along the negative x-axis.

z = 1.4*atan2(y, x)
Phase Transitions & Symmetry Breaking
2D Quartic Symmetry-Breaking Potential z = α(x⁴ − βx² + y⁴ − βy²)

Landau free-energy surface displaying unstable central peak, four saddle passes, and four symmetric degenerate ground-state wells.

z = 0.18*(x^4 - 5*x^2 + y^4 - 5*y^2) + 2
Visual Cortex & Texture Filters
2D Gabor Oriented Filter Kernel z = e^(−αr²)·cos(kₓx + kᵧy)

Directionally selective localized wave packet achieving the Heisenberg uncertainty bound simultaneously in space and spatial frequency.

z = 2.8*exp(-0.22*(x^2 + y^2))*cos(2.2*x + 1.1*y)
Solid-State Tight-Binding Bands
2D Square-Lattice Tight-Binding Dispersion E(kₓ, kᵧ) = −2t(cos kₓ + cos kᵧ)

Electronic energy band surface of a 2D square crystal lattice showing Van Hove saddle singularities along diamond Fermi contours.

z = 1.8*(cos(1.3*x) + cos(1.3*y))
Spectroscopy & Field Profiles
Anisotropic 2D Lorentzian Resonance Peak z = A / (1 + αx² + βy²)

Heavy-tailed rational surface modeling focused laser beam intensity profiles and 2D nuclear magnetic resonance spectral peaks.

z = 4.2 / (1 + 0.45*(x^2 + 1.8*y^2))
Interferometry & Hyperbolic Fringes
Hyperbolic Interferogram Surface z = A·sin(α(x² − y²))

Produces nested hyperbolic crest-and-trough fringes seen in astigmatic optical wavefront interferometry.

z = 1.6*sin(0.5*(x^2 - y^2))
Ruled Surfaces & Kinematics
Regularized Plücker Conoid z = 2xy / (x² + y² + ε) — Double-Wave Gear Surface

Smoothly regularized conoid oscillating as sin(2θ) around every circle, illustrating directional limit dependence near the origin.

z = (2.4*x*y) / (x^2 + y^2 + 0.25)

3. Exact Step-by-Step Matrix & Linear Algebra Solvers (18)

Row Reduction & Echelon Form
Gauss–Jordan RREF Calculator (Step-by-Step Exact Fraction Row Operations)

Transforms any matrix into canonical Reduced Row Echelon Form using exact GCD-simplified rational elementary row operations.

3×4 · RREF
Linear Systems Ax = b
3×3 Linear System Solver Ax = b — Exact Augmented Matrix Elimination

Solves 2x₁ + x₂ − x₃ = 8, −3x₁ − x₂ + 2x₃ = −11, −2x₁ + x₂ + 2x₃ = −3 to exact solution (2, 3, −1) with zero residual.

3×3 · SYSTEM
Engineering & Mesh Analysis
4×4 Symmetric Laplacian Linear System — Heat Grid & Kirchhoff Node Solver

Solves diagonally dominant 4-node steady-state Laplace finite-difference / resistor mesh equations with exact rational fractions.

4×4 · SYSTEM
Parametric Solution Spaces
Infinite-Solutions Parametric System Solver — Particular + Free-Variable Basis

Identifies pivot vs. free variables when rank(A) = rank([A|b]) < n and constructs full vector solution x = x_p + t₁v₁ + t₂v₂.

3×4 · SYSTEM
Rank & Consistency Diagnosis
Inconsistent Linear System Detector — Rouché–Capelli Contradiction Proof

Demonstrates step-by-step how rank(A) < rank([A|b]) produces an explicit contradiction row 0 = 4, proving zero solutions exist.

3×3 · SYSTEM
Determinants & Volume Scaling
3×3 Determinant Calculator — Upper-Triangular Pivot Reduction & Sign Tracking

Computes exact determinant via Gaussian elimination while tracking row-swap parity (−1)^s and parallelepiped volume orientation.

3×3 · DET
Higher-Order Determinants
4×4 Matrix Determinant Calculator — O(n³) Pivot Elimination vs. 24 Permutations

Avoids 24-term Leibniz cofactor expansion by reducing 4×4 matrices cleanly to four exact rational diagonal pivots.

4×4 · DET
Matrix Inversion
3×3 Matrix Inverse Calculator [A | I] → [I | A⁻¹] — Exact Rational Entries

Augments A with the identity matrix I₃ and executes full Gauss–Jordan elimination to extract exact rational A⁻¹.

3×3 · INVERSE
Numerical Conditioning Benchmarks
Hilbert 3×3 Matrix H₃ Exact Rational Inverse — Why Exact Fractions Beat Floats

Recovers exact integer inverse [[9,−36,30],[−36,192,−180],[30,−180,180]] and det(H₃) = 1/2160 without floating-point rounding loss.

3×3 · INVERSE
Rank Deficiency & Singularity
Singular Matrix Rank Diagnosis — Why [[1,2,3],[4,5,6],[7,8,9]] Has No Inverse

Reveals R₃ − 2R₂ + R₁ = 0 during row reduction, proving rank(A) = 2 < 3 and det(A) = 0.

3×3 · INVERSE
Spectral Theory & Eigenvalues
3×3 Symmetric Matrix Eigenvalues, Characteristic Polynomial & Eigenvectors

Computes characteristic polynomial λ³ − 12λ² + 45λ − 54 = 0, spectral eigenvalues λ = 6, 3, 3, and real eigenvectors.

3×3 · EIGEN
Complex Eigenvalues & Dynamical Systems
2×2 Rotation–Scaling Matrix Complex Conjugate Eigenvalues λ = 3 ± 4i

Explains why spiral rotation-dilation matrices have negative discriminant Δ < 0 and complex conjugate eigenvalues α ± βi.

2×2 · EIGEN
Stochastic Processes & Markov Chains
Markov Transition Matrix Perron–Frobenius Eigenvalue λ₁ = 1 & Mixing Rate

Analyzes doubly stochastic transition matrices where dominant eigenvalue λ₁ = 1 governs stationary equilibrium and |λ₂| controls convergence speed.

3×3 · EIGEN
Fundamental Subspaces & Rank-Nullity
Nullspace N(A) & Column Space C(A) Basis Calculator — Rank-Nullity Theorem

Extracts pivot columns of A for Col(A) and special free-variable vectors for Null(A), verifying rank(A) + nullity(A) = n.

3×4 · SUBSPACES
Matrix Factorizations
PA = LU Matrix Factorization Calculator with Partial Row Pivoting

Decomposes square matrices into permutation P, unit lower-triangular L, and upper-triangular U factors for fast multi-RHS solves.

3×3 · LU
Orthogonalization & Least Squares
Modified Gram–Schmidt QR Orthogonalization Calculator (A = Q·R)

Orthonormalizes the columns of classic Golub–Van Loan benchmark [[12,−51,4],[6,167,−68],[−4,24,−41]] into orthogonal Q and upper-triangular R.

3×3 · QR
Polynomial Interpolation
4×4 Vandermonde Interpolation System — Exact Cubic Curve Fitting

Determines exact cubic coefficients c₀ + c₁x + c₂x² + c₃x³ passing through (−1,2), (0,1), (1,2), and (2,11).

4×4 · SYSTEM
Combinatorial Matrices
4×4 Symmetric Pascal Matrix — Unimodular det(P₄) = 1 & Triangular Factors

Binomial-coefficient matrix Pᵢⱼ = C(i+j, i) whose LU triangular factors have unit diagonals, forcing det(Pₙ) = 1 for every dimension n.

4×4 · LU

4. Symbolic Calculus, Quadrature, Taylor & Fourier Series (18)

Symbolic Differentiation
Product & Chain Rule Differentiator: d/dx [x²·e^(−0.5x)] & Tangent Line

Applies symbolic Product and Chain rules step-by-step, locating stationary extrema at x = 0 and x = 4 plus concavity inflections.

x^2 * exp(-0.5*x)
Symbolic Differentiation
Quotient Rule Symbolic Derivative: d/dx [(x² + 1)/(x² − x + 2)]

Derives exact rational first and second derivatives, curvature κ(x₀), and bounded global extrema without pole singularities.

(x^2 + 1) / (x^2 - x + 2)
Trigonometric Calculus
Trigonometric Superposition Derivative, Stationary Extrema & Inflections

Finds all stationary maxima, minima, roots, and concavity sign-flips across [−π, π] with live tangent line visualization.

sin(2*x) + 0.5*cos(x)
Antiderivative Verification
Symbolic Verification d/dx [x·arctan(x) − ½ln(1 + x²)] = arctan(x)

Classic integration-by-parts identity where terms x/(1+x²) cancel algebraically to leave f′(x) = arctan(x) and f″(x) = 1/(1+x²).

x*atan(x) - 0.5*ln(1 + x^2)
Numerical Quadrature
Non-Elementary Gaussian Integral ∫ e^(−x²) dx — Riemann vs. Simpson vs. Gauss

Evaluates ∫₋₂² e^(−x²) dx = √π·erf(2) ≈ 1.76416278 across 6 quadrature rules, revealing exponential accuracy gain.

exp(-x^2)
Statistical Probability Integrals
Standard Normal 95% Confidence Area ∫₋₁.₉₆¹.⁹⁶ φ(z) dz = 0.950004

Shades and integrates the famous ±1.96σ two-tailed statistical threshold to 7-digit Gauss–Legendre precision.

exp(-x^2 / 2) / sqrt(2*pi)
Oscillatory Integrals & Optics
Fresnel Oscillatory Integral ∫₀³ sin(x²) dx — High-Frequency Quadrature Test

Rapidly chirping optical diffraction integral testing midpoint/trapezoid cancellation errors against 192-node Gauss–Legendre quadrature.

sin(x^2)
Geometric Area, Arc Length & Solids
Semicircle Integral ∫₋₂² √(4 − x²) dx = 2π, Arc Length 2π & Sphere Volume 32π/3

Simultaneously verifies area = 2π ≈ 6.283185, arc circumference = 2π, and solid-of-revolution sphere volume V = (4/3)π(2)³ ≈ 33.5103.

sqrt(max(0, 4 - x^2))
Logarithmic Quadrature
Exact Unit Integral ∫₁ᵉ ln(x) dx = [x·ln(x) − x]₁ᵉ = 1

Classic benchmark integral evaluating to exactly 1, illustrating concave-down trapezoidal underestimation vs. midpoint overestimation.

ln(x)
Signal Processing Integrals
Wilbraham–Gibbs Sine Integral Si(π) = ∫₀^π (sin x / x) dx ≈ 1.851937

Computes Si(π) ≈ 1.85193705, exceeding π/2 ≈ 1.570796 by the exact 8.95% Fourier Gibbs overshoot ratio.

sinc(x)
Taylor & Maclaurin Polynomials
Maclaurin Polynomial of sin(x) = x − x³/3! + x⁵/5! − x⁷/7!

Overlays odd-degree alternating Maclaurin approximations onto sin(x), showing how each added term hugs another half-wavelength.

sin(x)
Taylor & Maclaurin Polynomials
Exponential Maclaurin Series e^x = 1 + x + x²/2! + x³/3! + … + xⁿ/n!

Every derivative f^(k)(0) = 1 generates clean reciprocal-factorial coefficients converging across all real x.

exp(x)
Radius of Convergence
Mercator Series ln(1 + x) = x − x²/2 + x³/3 − … & Convergence Wall at x = 1

Visually demonstrates why Taylor polynomials match ln(1+x) tightly inside (−1, 1] yet diverge wildly for x > 1 due to the pole at x = −1.

ln(1 + x)
Power Series & Poles
Geometric Power Series 1/(1 − x) = 1 + x + x² + x³ + … + xⁿ

Canonical geometric expansion with unit coefficients cₖ = 1 bounded strictly by the vertical asymptote at x = 1.

1 / (1 - x)
Fourier Harmonic Analysis
Fourier Series of a Square Wave (4/π)·Σ sin((2k−1)x)/(2k−1) & Gibbs Phenomenon

Synthesizes odd sine harmonics 1, 3, 5, … up to N = 25, measuring RMS energy error and persistent 9% jump-discontinuity ringing.

Fourier(square)
Fourier Harmonic Analysis
Sawtooth Wave Fourier Synthesis (2/π)·Σ (−1)^(n+1) sin(nx)/n

Contains both odd and even integer harmonics decaying as 1/n, foundational to subtractive audio synthesizer waveforms.

Fourier(sawtooth)
Fourier Harmonic Analysis
Triangle Wave Cosine Fourier Series — Rapid 1/n² Gibbs-Free Convergence

Continuity of the triangle wave accelerates Fourier decay to 1/n², reaching near-visual perfection in just 5 harmonics.

Fourier(triangle)
Power Electronics & Harmonics
Full-Wave Bridge Rectifier |sin x| Fourier Spectrum — DC Component 2/π & Ripple

Extracts DC average a₀/2 = 2/π ≈ 0.63662 plus even ripple harmonics cos(2nx)/(4n² − 1) for AC-DC filter capacitor design.

Fourier(rectified)

5. First-Order ODE Slope Fields & RK4 Models (12)

Thermal & First-Order Linear ODEs
Newton’s Law of Cooling dy/dt = −k(y − T_env) — Exponential Attractor Line

All trajectories exponentially approach horizontal equilibrium asymptote y = 1 regardless of initial temperature y(0).

dy/dx = -0.6*(y - 1)
Population Dynamics & Equilibria
Verhulst Logistic Differential Equation dy/dt = r·y(1 − y/K) — Phase Stability

Autonomous phase portrait contrasting unstable extinction equilibrium y = 0 against stable carrying capacity y = 3.

dy/dx = 0.8*y*(1 - y/3)
Nonlinear Bifurcation & Memory
Bistable Cubic ODE dy/dt = α·y(4 − y²) — Two Attractors & Separatrix Threshold

Initial states y(0) > 0 snap to upper attractor y = +2 while y(0) < 0 snap to y = −2, modeling Schmitt triggers and genetic switches.

dy/dx = 0.25*y*(4 - y^2)
Electrical Transients & Steady State
AC-Driven RC Low-Pass Filter ODE dy/dt + (1/RC)y = A·cos(ωt)

Shows transient initial offset decaying away until all RK4 trajectories lock onto the same phase-lagged sinusoidal steady state.

dy/dx = 2*cos(1.8*x) - 0.9*y
Separable Differential Equations
Separable ODE dy/dx = −kxy — Family of Gaussian Bell Solutions y = C·e^(−kx²/2)

Compares Euler’s 1st-order drift against 4th-order Runge–Kutta (RK4) across symmetric Gaussian peak trajectories.

dy/dx = -0.6*x*y
Nonlinear Riccati Equations
Riccati Nonlinear Differential Equation dy/dx = a·x² − b·y² (Airy Reduction)

Non-separable quadratic ODE appearing in optimal LQR control theory and WKB quantum tunneling approximations.

dy/dx = 0.25*x^2 - 0.35*y^2
Ecological Modelling & Tipping Points
Logistic Population with Seasonal Harvesting dy/dt = y(1 − y/K) − H(t)

Reveals seasonal limit-cycle oscillation above critical biomass vs. sudden population collapse below the saddle-node separatrix.

dy/dx = y*(1 - y/3) - 0.55*(1 + 0.6*sin(2*x))
Oncology & Actuarial Growth
Gompertz Asymmetric Growth ODE dy/dt = α·y·ln(K/y) — Inflection at K/e

Unlike symmetric logistic growth (inflection at K/2), Gompertz growth inflects earlier at y = K/e ≈ 0.368K.

dy/dx = 0.55*y*ln(3.5 / max(0.05, abs(y)))
Bernoulli Differential Equations
Bernoulli Cubic ODE dy/dx − P(x)y = Q(x)y³ — Exact Linearization Benchmark

Transforms into a linear ODE via substitution u = y^(1−n) = y⁻², providing an exact closed-form check on RK4 numerical precision.

dy/dx = 0.5*y - 0.2*y^3
Variable-Coefficient Linear ODEs
Integrating Factor ODE dy/dx + y/(x + 4) = cos(x)

Multiplying by μ(x) = x + 4 yields exact derivative d/dx[(x+4)y] = (x+4)cos(x), solved alongside interactive RK4 trajectories.

dy/dx = cos(x) - y / (x + 4)
Isoclines & Asymptotic Funnels
Parabolic Nullcline Funnel dy/dx = x − αy² — Fence & Funnel Theorem

Demonstrates Hubbard’s antifunnel/funnel theorem as trajectories converge tightly onto the upper parabolic branch y ≈ √(x/α).

dy/dx = x - 0.35*y^2
Nonlinear Mechanics
Sinusoidal Force & Linear Drag ODE dy/dx = −A·sin(x) − γ·y

Illustrates periodic potential valleys with viscous damping pulling trajectories into stable phase basins.

dy/dx = -1.5*sin(x) - 0.35*y