Inverse Laplace Transform: Overview, Questions, Preparation

Inverse Trigonometric Functions 2021 ( Inverse Trigonometric Functions )

Updated on Jul 29, 2021 11:40 IST

Inverse Laplace Transform

The Laplace Transform is named after the French mathematician L. S. P. Laplace (1749-1827). As with other transformations, the Laplace Transform transforms one signal to another depending on one or a few fixed laws. The simplest approach to explain an equation is to turn it into an algebraic equation. 

Laplace Transform

The Laplace Transform is the integral transform of the specified derivative function to turn into a complex function with real variables. For a certain t, let f(t) be given (to fulfil the conditions mentioned above later on).

The Laplace Transform of an equation is described by the equation ‘f(t)=f(s) whenever the integration converges to zero.’

Where a notation is simple, I would write our Laplace Transforms with capital letters, e.g. L(f; s) = F(s). 

The Laplace Transform we described corresponds to the Laplace Transform available on only one hand. There is a two-sided representation of the integral that moves from negative infinity to positive infinity. 

Inverse Laplace Transforms

If the function y(a) is a continuous function, which is defined on [0, ∞) and also satisfies L[y(a)](b) = Y(b), then it is a Laplace Transform of Y. (b). 

You may use a piecewise continuous function over a given interval if the complementary function is continuous everywhere. 

L-1[Y(b)] (a) 

Definition of the Inverse Laplace Transform

The integral determines the Laplace Transform where Y(b) is the Y(a) of the function specified on [o, ∞].

Inverse Laplace Transform Table

To do the inverse transformation, use the table shown below.

Function y(a)

Transform Y(b)

b

1

1/b

b>0

a

1/b2

b>0

Ai , i = integer

    i!/s(i+1)

b>0

exp (ta), where t = constant

  1/(b-t)

b>t

cos (sa), s= constant

    b/(b2+s2)

b>0

Sin (sa), s = constant

    t/(b2+s2)

b>0

exp(ta)cos(sa)

    b-t/((b-t)2+s2)

b>t

exp(ta)sin(sa)

      s/((b-t)2+s2)

b>t

Inverse Laplace Transform in Class 12

This concept is taught under the chapter “Inverse Trigonometric Functions.” You will learn about the basics and formulas for inverse Laplace Transform. The weightage of this chapter is 8 marks.

Illustrated Examples

Find the inverse transform of each of the following:

Y(b)= 6/2b -1/(b−4) – 4/(b−2)

Solution:

Step 1: The first term is a constant as we can see from the first term’s denominator.

Step 2: Before taking the inverse transform, let’s take the factor 6 out, so the correct

the numerator is 6.

Step 3: The second term has an exponential t = 4.

Step 4: The numerator is perfect.

Step 5: The third term is also an exponential, t= 2.

Step 6: Now, before taking the inverse transforms, we need to factor out 4 first.

Y(b) = 6.1/2b -1/(b−4) – 4.1/(b−2)

y(a) = 6(2) – e^4a +4^(e2t)

= 12 – e^4a +4e^2t

FAQs

Q: What is s in Laplace transformation?

A: The Laplace Transform of a function is the unilateral transform described by F(s), where s is the real variable.

Q: What does the inverse Laplace Transform do?

A: If a function F(s) has Laplace’s inverse f(t), so the inverse Laplace Transform is uniquely defined (considering functions that differ from each other only on a point set having Lebesgue measure zero as the same).

Q: Is the Laplace Transform nonlinear?

A: The Laplace Transform of an operation is the Laplace Transform of the function that the operation is applied to. 

Q: Can you multiply the Laplace Transform?

A: Since the Laplace Transform is continuous, only its inside and outside should be multiplied by -1.

Q: Why are the Laplace Transforms important?

A: One benefit of using the Laplace transformation to solve differential equations is that the initial conditions are immediately converted into the answer, meaning one does not have to locate the homogeneous solutions and individual solutions separately.
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Inverse Trigonometric Functions Exam

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