Applying Partial Fractions to Solve Laplace Step Function Problems

In summary, the conversation discusses the use of partial fractions to solve a differential equation and the process of finding the constants A, B, and C. The final step involves taking the Laplace transform of the equation.
  • #1
myusernameis
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step function - laplace...

Homework Statement


y"+y = f(t)

f(t) = 1, t<pi/2
0, pi/2<=t<infinity

The Attempt at a Solution



i now have L{y} = [tex]\frac{1-e^(-(pi/2)s)+s}{s(s^2+1)}[/tex]

but how do i separate them and finish the problem?

thanks
 
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  • #2


Use partial fractions like always.
[tex]\frac{1}{s(s^2+ 1)}= \frac{A}{s}+ \frac{Bs+ C}{s^2+ 1}[/tex]

Find A, B, and C.
 
  • #3


HallsofIvy said:
Use partial fractions like always.
[tex]\frac{1}{s(s^2+ 1)}= \frac{A}{s}+ \frac{Bs+ C}{s^2+ 1}[/tex]

Find A, B, and C.

so no i have f(t) = 1-cos(t)+sin(t) - L{[tex]\frac{e^(pi*t/2)}{s(s^2+1)}[/tex]}

how do i get the last laplace?
 
Last edited:

FAQ: Applying Partial Fractions to Solve Laplace Step Function Problems

What is a step function in Laplace domain?

A step function in Laplace domain is a piecewise constant function that changes abruptly at a specific time, t=0. It is often used to model systems that have an immediate change in their behavior at a certain point in time.

How is a step function represented in the Laplace domain?

A step function is represented by the Heaviside function, also known as the unit step function, in the Laplace domain. It is denoted by the symbol u(t) and is defined as 1 for t>0 and 0 for t<0. The Laplace transform of a step function is 1/s.

What is the significance of step functions in Laplace domain?

Step functions play a crucial role in solving differential equations using the Laplace transform. They help to simplify the mathematical expressions and make the solutions more manageable, especially in cases where the input or output of a system has a sudden change.

How is the Laplace transform of a step function derived?

The Laplace transform of a step function can be derived using the definition of the Laplace transform. By substituting the expression for the step function, u(t), into the integral and evaluating it, the Laplace transform of the step function can be obtained as 1/s.

Can a step function have multiple jumps in the Laplace domain?

Yes, a step function can have multiple jumps in the Laplace domain. In this case, the Laplace transform of the step function will have multiple terms, each corresponding to a different jump in the function. This allows for modeling of more complex systems with multiple changes in their behavior at different times.

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