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Laplace Transform Calculator – Basic Functions

Quick answer

L¹{f}(s)=∫₀^∞e⁻ˢᵗf(t)dt for standard inputs: L{1}=1/s, L{e²ᵗ}=1/(s−2), L{t}=1/s², L{sin t}=1/(s²+1).

  • Shift rules and table included.

Figures are estimates from this calculator’s standard formula — adjust the inputs in the tool below for your exact number.

How the Laplace Transform Calculator Works

F(s) = ∫₀^∞ e⁻ˢᵗ f(t) dt

The Laplace transform swaps time-domain calculus for s-domain algebra. Integrating e⁻ˢᵗ against f(t) from 0 to infinity converts the library: constants pass through as L{1} = 1/s; exponentials shift the pole, L{e²ᵗ} = 1/(s−2); powers fall factorial-wise, L{t} = 1/s² and L{t²} = 2/s³; sines and cosines produce quadratic denominators, L{sin t} = 1/(s²+1) and L{cos t} = s/(s²+1). The calculator evaluates the integral pattern for each supported form and demonstrates the operational rules that make the transform useful: differentiation becomes multiplication, L{f′} = sF(s) − f(0), so an ODE turns into an algebra equation. Shifting: L{eᵃᵗf(t)} = F(s−a), and delay: L{f(t−c)} = e⁻ˢᶜF(s). Convergence needs s larger than the growth rate — e²ᵗ requires s > 2.

  1. 1

    Choose a function form

    1, tⁿ, eᵃᵗ, sin(bt), cos(bt), or composites

  2. 2

    Read the transform pair

    F(s) is returned with the integral substitution

  3. 3

    Apply the rules

    Shift, delay, and derivative rules are demonstrated

  4. 4

    Check convergence

    The valid s-range (s > a for exponentials) is stated

Use Cases

ODE Solving

Convert y″ + y = 0 into algebra, solve, invert

Circuit Transients

RLC responses come straight from transform tables

Control Theory

Transfer functions are Laplace ratios G(s) = Y(s)/U(s)

Tips

  • 1

    Derivatives map to polynomials in s: L{f′} = sF(s) − f(0)

  • 2

    L{eᵃᵗf} = F(s−a) — exponential factors shift the s-domain

  • 3

    Convergence requires s above the function’s growth exponent

Common Mistakes

  • Dropping the initial-condition term f(0) when transforming derivatives

  • Using L{eᵃᵗ} = 1/(s+a); the pole sits at s = a, giving 1/(s−a)

  • Forgetting the factorial: L{t²} = 2/s³, not 1/s³

  • Ignoring the s > a convergence requirement for exponentials

FAQs

What is L{1}?

1/s for s > 0 — the integral of e⁻ˢᵗ from 0 to ∞.

What is L{e²ᵗ}?

1/(s−2), valid for s > 2 — the pole shifts to +2.

What is L{sin t}?

1/(s²+1); correspondingly L{cos t} = s/(s²+1).

Why do engineers use Laplace transforms?

They convert differentiation into multiplication by s, turning differential equations into algebra.

What is the derivative rule?

L{f′} = sF(s) − f(0): e.g. for f = e²ᵗ, s/(s−2) − 1 = 2/(s−2) ✓.