standarddeviationcalculator.net

Updated

Calculus calculators

Step-by-step calculators for derivatives, integrals and limits, plus series, differential equations and functions of two variables. Each names the rule or test it applies at every step, for students working through a calculus course.

Which calculator do I need?

You have or wantUse
The derivative of a function, with the chain, product or quotient rule shownDerivative calculator
An antiderivative, or the area under a curve between two limitsIntegral calculator
The limit of a 0/0 or ∞/∞ expressionLimit calculator
Whether an infinite series converges, and its sumInfinite series calculator
A numerical solution of y′ = f(x, y) from a starting valueDifferential equation calculator
∂f/∂x, ∂f/∂y and the mixed partials of f(x, y)Partial derivative calculator
The gradient, critical points or a double integral of f(x, y)Multivariable calculus calculator

Limits and derivatives

Rates of change of a function of one variable, and the limits they are built on.

Integrals and series

Adding up: areas under curves, and sums of infinitely many terms.

Differential equations and several variables

Equations involving derivatives, and functions of more than one variable.

How the calculus tools connect

A derivative is a limit, and an integral undoes a derivative, so the first three calculators cover the core of a single-variable course. The limit calculator handles the indeterminate forms that make limits hard. The derivative calculator gives up to the fourth derivative and the tangent line. The integral calculator names the method it used, such as substitution, by parts or partial fractions.

The rest extend these ideas. The series calculator applies convergence tests. The differential equation calculator solves equations where the unknown is a function. The partial derivative and multivariable calculators take everything to functions of two variables.

Worked comparison: one function, three questions

Take f(x) = x³ − 3x. Its derivative is f′(x) = 3x² − 3, which is zero at x = −1 and x = 1. Those are the turning points: a local maximum of 2 at x = −1 and a local minimum of −2 at x = 1. The definite integral from 0 to 2 is [x⁴/4 − 3x²/2] from 0 to 2 = 4 − 6 = −2. The answer is negative because more of the curve lies below the axis on that interval than above it. A signed integral is not the same as the geometric area.

Numerical methods and their accuracy

Solving y′ = y with y(0) = 1 up to x = 1 should give e ≈ 2.718282. With a step of 0.1, Euler’s method gives 1.1¹⁰ ≈ 2.593742, an error of about 5%. The fourth-order Runge–Kutta method (RK4) gives 2.718280 with the same step. The differential equation calculator shows both, so you can see why RK4 is the default.

Common mix-ups

  • Terms tending to zero is not enough. The terms of 1 + 1/2 + 1/3 + … shrink to zero, but the harmonic series diverges. By contrast, 1 + 1/4 + 1/9 + … converges to π²/6 ≈ 1.6449.
  • Forgetting + C. An indefinite integral is a family of functions, so the constant matters, especially when you solve a differential equation from an initial value.
  • Partial versus total derivative. ∂f/∂x holds y fixed. The gradient collects all the partials into one vector.

Guides to read alongside

Common questions

Why does the integral calculator give a decimal and no formula?
Some functions, such as e^(−x²) or sin(x)/x, have no antiderivative in elementary terms. For a definite integral the calculator then switches to a high-accuracy numerical method and says so, so you still get the value between your limits.
What is L’Hôpital’s rule and when does the limit calculator use it?
When a limit takes the form 0/0 or ∞/∞, you can replace the top and bottom with their derivatives and try again. The limit calculator applies it only in those cases, shows each round, and adds a table of values approaching the point as a check.
Is RK4 exact?
No. RK4 is a numerical method with an error that shrinks roughly with the fourth power of the step size, so halving the step cuts the error about sixteen-fold. For linear first-order equations, the differential equation calculator also gives the exact solution to compare against.