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Topic: Double integration
Replies: 10   Last Post: Dec 6, 2011 12:42 PM

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Posts: 29
Registered: 10/6/08
Double integration
Posted: Dec 1, 2011 1:18 PM
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Dear friends

I've been trying to solve this double integration with the help of MatLab but apparently I am missing something.

INT (3,5) INT (0,SQRT(25-x^2)) SQRT((16x^2+16y^2-625)/(x^2+y^2-25)) dydx

The above is not in any standard syntax, but perhaps will communicate the actual problem. The integration on y is from 0 to SQRT(25-x^2) and the integration on x is from 3 to 5.

This is the m file:
syms x y
firstint = int(sqrt((16*x*x+16*y*y-625)/(x*x+y*y-25)),y,0,sqrt(25-x^2))
answer = int(firstint,x,3,5)

and this is the error message I have got:

??? Attempt to call constructor double with incorrect letter case.
Error in ==> sym.sym>sym.sym/symnumeric at 152
S{k} = symr(double(x(k)));
Error in ==> sym.sym>sym.sym at 116
S = cell2sym(S,symnumeric(x,a));
Error in ==> sym.times at 8
A = sym(A);
Error in ==> sym.eval at 14
s = evalin('caller',vectorize(map2mat(char(x))));

Many thanks

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