Quad Function Error for Integrals

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Hello, I have spent the last 2 hours trying to figure out why the quad function (required to use instead of integral function by my professor) is not working. MatLab just tells me there is an error with my code but does not go into any specifics into what the error might be, making it very difficult & frustrating to debug. Anyways, I need to use the quad function to calculate the following integrals. The first equation y1 works, but y2 & y3 come up with an error. How do I fix this?
y1 = quad('x.^2 +2*x+3',0 , 3)
y2 = quad('(.5*x.^3)/(1+2*sqrt(x))', 2, 10)
y3 = quad('.5 + ((cos(1.2*x))/((x+2)^2))', 0, 9)

Accepted Answer

David Goodmanson
David Goodmanson on 7 Apr 2017
Hello Adriel, you are missing some dots to make element-by-element division and exponentiation happen
y1 = quad('x.^2 +2*x+3',0 , 3)
y2 = quad('(.5*x.^3)./(1+2*sqrt(x))', 2, 10)
^
y3 = quad('.5 + ((cos(1.2*x))./((x+2).^2))', 0, 9)
^ ^
  2 Comments
Adriel Martinez-Alvarez
Adriel Martinez-Alvarez on 7 Apr 2017
Ah, I see. Thank you for your quick answer. I can't believe I spent so much time on something so simple.
David Goodmanson
David Goodmanson on 7 Apr 2017
Yes, I think we have all been there. You look at something 25 times and never see what's hiding in plain sight.

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