Simple Calculator Online: Free Basic Calculator
A free simple calculator for everyday arithmetic, with brackets, percentages and history, plus quick guides to order of operations and percent problems.
Guides & worked examples
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Free Scientific Calculator Online (with DEG/RAD Guide)
A free online scientific calculator with trig in degrees or radians, logs, powers, roots, factorials and scientific notation, plus how to use every key.
Euler’s Method: Formula and Step-by-Step Example
Euler’s method approximates solutions of y’ = F(x, y) with yₙ₊₁ = yₙ + h·F(xₙ, yₙ). A full worked table, error behavior, and a comparison with RK4.
Double Integrals: How to Evaluate Them Step by Step
Evaluate double integrals as iterated integrals, switch the order of integration, and use polar coordinates. Step-by-step worked examples.
Gradient and Directional Derivative: Formulas and Examples
The gradient ∇f collects partial derivatives; the directional derivative D_u f = ∇f · u gives the slope in any direction. Worked example and geometric meaning.
Partial Derivatives: How to Calculate Them (with Examples)
A partial derivative differentiates in one variable, holding the others constant. Notation, examples, second partials and Clairaut’s theorem.
Geometric Series Formula: Sum, Convergence and Examples
An infinite geometric series a + ar + ar² + … sums to a/(1 − r) when |r| < 1. Finite sum formula, derivation, repeating decimals and worked examples.
Ratio Test for Series Convergence: How to Use It (Examples)
The ratio test: if lim |aₙ₊₁/aₙ| < 1 the series converges, > 1 it diverges, = 1 inconclusive. Worked examples with factorials, powers and radius of convergence.
Taylor and Maclaurin Series: Formula and Examples
The Taylor series formula, how to build Taylor polynomials step by step, a table of common Maclaurin series (eˣ, sin x, cos x, ln(1+x)), and error bounds.
Squeeze Theorem: Statement, How to Use It and Examples
The squeeze (sandwich) theorem finds limits by trapping a function between two others. Step-by-step examples with x²·sin(1/x), sin(x)/x and cos(x)/x.