how to estimate/evaluate the integral of a constant value function?

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Jinquan Li
Jinquan Li 2021-2-23
评论： Jinquan Li 2021-2-23
For example, f = 5, for 0<t<1, zero otherwise.
i tried the following code but it didn't work:
syms t
f = 10;
int(f)

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采纳的回答

Walter Roberson
Walter Roberson 2021-2-23
编辑：Walter Roberson 2021-2-23
Ran in:
syms t a b real
f = piecewise(0 < t & t < 1, 5, 0)
f = 
int(f, t, a, b)
Warning: Unable to check whether the integrand exists everywhere on the integration interval.
ans = 
  1 个评论
Jinquan Li
Jinquan Li 2021-2-23
thanks. this works. Now i have another question. What if i use numerical integration? Here is what i tried:
f1 = @(t) piecewise(0<t & t<1, 10, 0);
q = integral(f1,0,1)

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更多回答（1 个）

Just Manuel
Just Manuel 2021-2-23
Try this:
syms t
f = 0*t + 10;
int(f);
Cheers Manuel
  3 个评论
显示 1更早的评论
Just Manuel
Just Manuel 2021-2-23
编辑：Just Manuel 2021-2-23
you can't use piecewise in a numerical context. redefine your function as follows:
f = @(t) 5 .* (t > 0 & t < 1);
% then you can calculate numerical integral like this
integral(f, -1, 1)
Cheers
Manuel

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