How to calculate the integration with Matlab?

I need support in calculating integration of function below. I tried to use int(), integral() in matlab documentation, but it did not work. You can help me either by providing key works so that I google it, or providing me matlab code as an example for later use. Thanks

[Jan]

This looks like a homework question: "10pt". Then please post, what you have tried so far and ask a specific question. See how-do-i-get-help-on-homework-questions. Thanks.

[Rena Berman]

(Answers Dev) Restored edit

Answer 1

[Birdman]

Try this:

syms U(t) X(t) s
R=0.01;C=4;
U(t)=piecewise(t<0,0,t>=0,sin(100*pi*t));
fun(s)=exp(-s/(R*C))*U(t-s);
X(t)=(1/R*C)*int(fun,s,0,Inf);
t=0:0.001:0.2;
Xt=X(t); %X(t) function is calculated for t vector
plot(t,Xt)

[Trung Khoa Le]

Thanks for your response 1. Please show me command to print the values of Xt? 2. Instead of using 'piecewise', do we have other ways, like 'if else' statement, to execute the same?

[Birdman]

show me command to print the values of Xt

 disp(Xt)

Instead of using 'piecewise', do we have other ways, like 'if else' statement, to execute the same?

Yes but piecewise is quicker.

[Jan]

@Birdman: It is questionable, if solving a homework is useful for the OP.

[Birdman]

He said he used int(), integral() and was unable to solve the question. I believe that he showed effort.

[Trung Khoa Le]

Yes I did, first I tried syms t,s but it did not work, then I tried work-around solutions (searching on the Internet) to find out reasons, but could not find anything. It is homework but not mine. I just tried to do it as the way to learn Matlab ^^.

Answer 2

[Walter Roberson]

When you have a fixed number of samples then evaluate the function at the provided locations and use trapz()

[Trung Khoa Le]

Thanks, will try on your way in the future.