Integral with specific range (i.e t = 0:0.1:1)

Hello everybody,

I'm a new user of matlab and still a beginner of this software. I'm using matlab R2015a by the way.

I've made a function called intensityc (t) with this code:

%NHPP on critical component (N(t))

function lc = intensityc(t)

B = 2;

ac = 0.4;

lc = (B/ac)*((t/ac).^(B-1));

end

then I was trying to call the function to another function Lamdac (t) with this code:

%big Lamda

function Lc = Lamdac(t)

Lc = integral(@intensityc, 0 ,t);

end

I have a trouble to find the value of Lamdac(t) because the "t" is ranging from 0 up to 1. I have used 'Arrayvalued' but the code still error.

Anyone can help me? I will appreciate all suggestions given to me. Thank you.

Answer 1

[Star Strider]

Do the integration in a loop for each value of ‘t’:

function lc = intensityc(t)
    B = 2;
    ac = 0.4;
    lc = (B/ac)*((t/ac).^(B-1));  
end

function Lc = Lamdac(t)
    for k = 1:numel(t)
        Lc(k) = integral(@intensityc, 0 ,t(k));
    end
end

Calling it:

t = linspace(0, 1, 10);
Out = Lamdac(t).'

produces:

Out =
                   0
   0.077160493827160
   0.308641975308642
   0.694444444444444
   1.234567901234568
   1.929012345679012
   2.777777777777777
   3.780864197530863
   4.938271604938270
   6.249999999999999

(Another option is to use arrayfun, however it is much slower and less efficient than an explicit loop.)

[Fakhri Alifin]

thank you for your suggestion.

by the way I've tried to apply your code, but it still error and show error message that argument in Lamda (c) is not enough, could you give another suggestion? thank you so much for your help.

[Star Strider]

My pleasure!

My code as I posted it ran without error in R2020b, and produced the results I posted.

I do not understand what the problem is when you run it. What was the exact code you ran? How did you run it?

Note that you must run it from a script as I noted in my Answer:

t = linspace(0, 1, 10);
Out = Lamdac(t).'

You cannot run it by pressing the green Run arrow in the editor. It will not run correctly that way.

Please copy and paste the entire error message (all the red text that appears in your Command Window). That way, I may be able to understand.

[Fakhri Alifin]

Thanks for your help, it already work!

[Star Strider]

My pleasure!

If my Answer helped you solve your problem, please Accept it!

.