# Integration using matlab

by Execute
Tags: integration, matlab
 P: 2 Hi everyone, I have a problem in finding an integral of a function. I'm given the following function: x(t) = t + 1 (-1 <= t < o ); e^-t (0<= t <= 2); 0 (otherwise).I have to find the integral and plot it with its derivative and the given function. Here is my code: %Set up integral vector u(1:1000) = 0; %Find the integral for n = 1:999; if( (t(n)>= -1) & (t(n)<0) ); u(n) = 0.5.*(t.^2) + t; end if ( (t(n)>=0) & (t(n)<2) ); u(n) = -1.*(exp(-t)); end if( (t(n)>2 ) ) u(n) = 1.*t; end end subplot(3,1,3); plot(t,u); I get the following error when trying to run the code: ??? In an assignment A(I) = B, the number of elements in B and I must be the same. Error in ==> tut1 at 32 u(n) = 0.5.*(t.^2) + t;
P: 212
 Quote by Execute Error in ==> tut1 at 32 u(n) = 0.5.*(t.^2) + t;
In these three lines
     u(n) = 0.5.*(t.^2) + t;
u(n) = -1.*(exp(-t));
u(n) = 1.*t;
you are trying to store a vector in a scalar's place. u(n) is a scalar and t is a vector, so change t to t(n) and you will be fine. Also, be sure to define t properly (don't see it in your code), e.g. t = linspace(-1,2,1000).
 P: 1 i have 1 question how do i apply 1/s in simulink block to M-code, for example Xdot to X in simulink, we just apply the 1/s(integration block). so i just want to know, is it possible to integrate the Xdot to X in m code??

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