Double integration in simulink

Kindly guide me When I am doing double integral of constant 10 with time 10 sec it gives the result of 500 but when I am solving it by hand it gives the result of 1000. I am solving it as ---> integral_0^10 integral_0^10 10 dx dy = 1000 Images of solution and simulink is attached

[Jesus Velazquez]

What you have in Simulink is not the same as your original integral.

In Simulink, you have:

10 int_0^10 x dt

That results in 10x^2/2, which would yield 10(100)/2 = 500

I really don't know how you can do what you want.

[mahmood hassan]

Yes, What I have in Simulink is not the same as my original double integral. as integral_0^10 integral_0^10 (10 )dx dy = 1000 always gives the result of 1000 but why simulink is giving the result of 500

[mahmood hassan]

I can not understand your method to solve double integral of 10 with initial time 0 and final time 10. you wrote this way 10 int_0^10 x dt That results in 10x^2/2, which would yield 10(100)/2 = 500 can you explain it step by step?

[Jesus Velazquez]

simulink will integrate twice, but over the same variable (time), that's why you are never going to get 1000.

Your first integrator does int 10 dt, then it goes into the second one, which does int 10 x dt. That results in 10x^2/2

[mahmood hassan]

Thanks a lot, Jesus Velazquez. I got your point.

[mahmood hassan]

Hi, May you guide me when I am doing a double integration of step function having properties (initial value =10, final value =5, step time =5) over total time = 10s.

why it does not gives the result of

result = 5 int_0^5 x dt + 10 int_5^10 x dt

result = 5x^2/2 + 10x^2/2

result = 62.5+375=437.5

But result in simulink is 312.5.

I will be thankful to you.

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[Jesus Velazquez]

That one is a bit more complicated

Answer 1

[Sean de Wolski]

integral2(@(x,y)10+zeros(size(x)), 0, 10, 0, 10)

[mahmood hassan]

I want to do double integral by simulink not by coding. kindly explain about the difference in Answer of double integral by simulink and by hand as shown in pix