ECET 345 LAB Week 2 Laplace Transform
ECET 345
LAB WEEK 2
Last week was a basic introduction to Matlab. This week you will learn how to use three built-in functions (laplace, ilaplace and dsolve).
Using the syms function
An expression can be represented using symbols with the syms function.
Let’s study the following example:
syms x y % Declare two symbolic variables x and y
y = x^2 %Declare a function
z=diff(y) %Will calculate the derivative of y and store the value in z.
How to find the Laplace transform for an expression?
Example: Find the Laplace transform of sin(2t). From the table of Laplace transforms, the Laplace transform of sin(2t) is . Let us do the same calculation in Matlab.
syms t % Declare a symbolic variable t
F=laplace(sin(2*t)) %Calculate Laplace transform, store in F
pretty(F) % print the output in a more readable form
How to find the inverse Laplace transform for an expression?
Example: Find the inverse Laplace transform of From the previous example, the inverse Laplace transform is sin(2t). The following code will verify this calculation in Matlab.
syms s % Declare a symbolic variable s (the Laplace variable)
f=ilaplace(2/(s^2+4)) %Calculate inverse Laplace transform, store in F
pretty(f) % print the output in a more readable form
How to solve a differential equation in Matlab?
Example: Solve the differential equation , with initial conditions x(0)=1 and x’(0)= 0.
Matlab command:
dsolve('D2x+2*x=0', 'x(0) = 1, Dx(0) = 0')
Exercises:
1. Find the Laplace transforms of the following functions by hand and verify results using Matlab.
1.
2.
3.
2. Find the inverse Laplace transform of the following functions by hand and verify results using Matlab.
1.
2. F(s)=
3. Solve the following differential equations by hand and verify results using Matlab.
with x(0) = 1, x' (0) = 0
with x(0) = 1, x' (0) = 0
laplace question 1 and 2 solution
Exercises: Find the Laplace transforms of the following functions by hand and verify results using Matlab. General Laplace transform table F(t) f(t) 1 1/s t^n n!/s^(n+1) e^at/e^(-at) 1/(s-a)/1/(s+a) sinax a/(s^2+a^2 ) cosax s/(s^2+a^2 ) y y ̃ y^̕ ̕sy ̕-y(0) y̋ s^2 y ̄-sy(0)-y ̕(0) x(t)=t Hand calculation ɭ[x (t)] =∫_0^∞▒〖x(t)e^(-st) dt〗 = ∫_0^∞▒〖te^(-st) dt〗 Using differentiation by parts Let u=t and dv=e^(-st) du=1 and also v will be v=〖-e〗^(-st)/s x(t)= ∫_0^∞▒〖te^(-st) dt〗=〖-te〗^(-st)/s ǀ_0^∞ +1/s ∫_0^∞▒〖e^(-st)...laplace question 1 and 2 solution
ECET 345 LAB WEEK 2 Last week was a basic... The Laplace transformxxxxxxxxxx functions into f(t) that are defined by whereby: Laoplace transforms the f(t)xxxxxxxxxxx function that can also be obtained with a Matlab’s function Laplace. The...laplace question 1 and 2 solution
This Tutorial is rated A+ p...laplace question 1 and 2 solution
ECET 345 LAB WEEK 2 Last week was a basic... The Laplace transforms functions into f(t) that are defined by whereby: Laoplace transforms the f(t) function that can also be obtained with a Matlab’s function Laplace. The syntax is L=laplace(f)...
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