# Laplace Transform Calculator

## Calculate the Laplace transform

The calculator will try to find the Laplace transform of the given function.

Recall that the Laplace transform of a function is $F(s)=L(f(t))=\int_0^{\infty} e^{-st}f(t)dt$.

Usually, to find the Laplace transform of a function, one uses partial fraction decomposition (if needed) and then consults the table of Laplace transforms.

Related calculator: Inverse Laplace Transform Calculator

The unit step function (Heaviside function) $u_c\left(t\right) = u{\left(t - c \right)} = \theta\left(t - c\right)$ should be entered as heaviside(t-c), the dirac delta function $\delta\left(t - c\right)$ should be entered as dirac(t-c).

If the calculator did not compute something or you have identified an error, or you have a suggestion/feedback, please write it in the comments below.

Use our Laplace Transform Calculator to find the Laplace Transform of a function. This tool is created to help you with your tasks.

## How to Use the Laplace Transform Calculator?

• ### Input

Enter the function $f(t)$ you want to transform in the specified field. Make sure there are no mistakes.

• ### Calculation

Once you've entered the function, click the "Calculate" button.

• ### Result

After the calculation, the Laplace transform of the given function will be displayed.

## What is the Laplace Transform?

The Laplace Transform is an integral transform that converts a function of a real variable $t$ (often time) to a function of a complex variable $s$. It has widespread applications in engineering, physics, and control theory.

Mathematically, the Laplace Transform $\mathcal{L}$ of a function $f(t)$ is given by the following formula:

$$\mathcal{L}_t\left(f(t)\right)=F(s)=\int_0^{\infty} e^{-st}f(t)dt,$$

where:

• $f(t)$ is a function of time $t$ defined for $t\ge0$.
• $e^{-st}$ is the exponential factor which weighs the function.
• $s$ is a complex variable, i.e. $s=a+bi$, where $a$ and $b$ are real numbers and $i$ is the imaginary unit.
• $F(s)$ is the Laplace Transform of $f(t)$.

## How to find the Laplace transform of a function?

To determine the Laplace transform of a function, its definition is used.

Steps to Find the Laplace Transform of a Function:

• Understand the Function: Start by understanding $f(t)$. The Laplace transform of many common functions has already been calculated, it can be memorized or found in a table.
• Set up the Integral: Write down the definition of the Laplace transform:

$$F(s)=\int_0^{\infty} e^{-st}f(t)dt$$
• Plug your function $f(t)$ into this integral.
• Integrate: Evaluate the integral from $0$ to $\infty$. This may involve integration by parts, trigonometric substitutions, or other integration techniques, depending on $f(t)$.
• Result: The resulting function in terms of $s$ is the Laplace transform of $f(t)$.

For example, find the Laplace Transform of $f(t)=t$.

Use the definition:

$$F(s)=\int_0^{\infty} e^{-st}tdt$$

To solve this integral, you use integration by parts: let $u=t$ and $du=e^{-st}dt$, then $du=dt$ and $v=-\frac{1}{s}e^{-st}$.

The formula for integration by parts is the following:

$$\int udv=uv-\int vdu$$

Apply the formula:

$$\int_0^{\infty} e^{-st}tdt=\left.-\frac{t}{s}e^{-st}\right|_0^{\infty}+\int_0^{\infty} \frac{1}{s}e^{-st}dt$$

The first term approaches zero as $t$ approaches $\infty$ due to the exponential term (assuming $s\gt0$).

The second integral evaluates to $\frac{1}{s^2}$.

Therefore, $F(s)=\frac{1}{s^2}$.

And that's the Laplace Transform of $f(t)=t$.

Tips:

• Familiarize yourself with common Laplace Transforms to simplify the process. Many functions' transforms can be found in reference tables.
• Practice makes perfect. The more functions you transform, the more familiar you'll become with various integration techniques and the more familiar you'll become with the Laplace transform.

Remember, the Laplace transform is a powerful tool for analyzing linear time-invariant systems, especially in control engineering. It is also used in signal processing.

## Why Choose Our Laplace Transform Calculator?

• ### Efficiency and Speed

Instantly compute the Laplace transform without tedious manual calculations. Save time and get your results in a fraction of a second.

• ### User-Friendly Interface

Created for straightforward use, our calculator boasts an intuitive interface. It's user-friendly for both novices and experts, eliminating the need for extensive learning.

• ### Reliability and Accuracy

Based on advanced algorithms, our calculator guarantees correct results.

### FAQ

#### What is the difference the Fourier and the Laplace Transforms?

The Fourier and Laplace Transforms are tools in signal processing and system analysis. While the Fourier Transform focuses on steady-state, periodic functions and converts them from the time to the frequency domain, the Laplace Transform covers both transient and steady-state scenarios, converting functions to the complex frequency domain, making it more versatile in handling initial conditions and transient behaviors.

#### What is the Laplace Transform's principal purpose?

The primary purpose of the Laplace Transform is to convert a function from the time domain (often denoted as the t-domain) to a function in the complex frequency domain (often denoted as the s-domain). This transformation simplifies the analysis and solution of linear differential equations, especially in systems engineering and control theory.

#### Can we solve differential equations using the Laplace transform calculator?

Although the Laplace transform is used to solve differential equations, this calculator only finds the Laplace transform of different functions. The use of the Laplace transform to solve differential equations is as follows:

• Convert the differential equation from the time domain to the s-domain using the Laplace Transform. The differential equation will be transformed into an algebraic equation, which is typically easier to solve.
• After solving in the s-domain, the Inverse Laplace Transform can be applied to revert the solution to the time domain.

#### What is the Laplace Transform, and why is it important?

The Laplace Transform converts time-dependent functions to the complex frequency domain, simplifying the analysis of linear systems. It's important in areas like control theory and engineering because it helps to solve complex differential equations.