Math & Numbers
Union, intersection, difference, symmetric difference, and Cartesian product of two comma-separated sets, with cardinalities and capped pair display.
set-operations-calculatorMath & Numbers
Table lookup of the unilateral Z-transform for 11 standard pairs, with parameter substitution, region of convergence, derivation note, and optional numeric X(z₀) evaluation.
z-transform-calculatorDesign
Resolve any hex color to its nearest CSS named color with true CIEDE2000 ΔE distance, then browse the whole color family it belongs to.
css-color-name-resolverMath & Numbers
Classical fourth-order Runge-Kutta for dy/dx = f(x, y): step table, k1–k4 stage details, final estimate, and optional exact-solution error column.
runge-kutta-rk4-solverMath & Numbers
Solve a·y'' + b·y' + c·y = f(x): characteristic roots, three homogeneous cases, undetermined coefficients with resonance, and C1/C2 from initial conditions.
second-order-ode-solverEducation
Convert A ↔ %T ↔ T with A = −log₁₀(T) and %T = 100·T; returns all three representations for spectrophotometry work.
absorbance-transmittance-converterDesign
Layered radial-gradient "mesh" backgrounds with conic underlays, blend modes, grain and seeded layouts — live preview, CSS and Tailwind export.
css-gradient-mesh-generatorMath & Numbers
Compute remaining radionuclide activity A(t) = A₀·2^(−t/T½) with λ = ln2/T½ in Bq/Ci/dpm units, for Tc-99m, F-18 and other isotopes.
half-life-activity-decayMath & Numbers
Carrier-free specific activity from the half-life: A = ln2·N_A/T½ in Bq/mol and Ci/mmol, with optional Bq/g and Ci/g from molar mass.
specific-radioactivityMedia
Add a subtle text watermark to one image or every supported image in a ZIP, at all, random, or chosen perimeter positions with automatic dark/light local contrast.
adaptive-12-point-hidden-watermarkMedia
Partially cover matching low-contrast text watermarks at all, random, or selected perimeter positions using a local Canvas patch.
adaptive-12-point-watermark-cover-restorerEducation
One value, three linked notations — pie, bar, percent grid and number line — with a live-synced slider, exact repetend detection and practice exercises.
fraction-decimal-percent-visualizer