How could I check my solution if I am doing a definite integration please?? I mean,since a definite integral is the limit of a sum so could I write a code using sum to check my results??

integral(f(x),a,b)=sum(f(xi),1,N)?

Answer 1

[Mischa Kim]

Avan, yes you could. For example:

 f = @(x) sin(x);
 a = 1;
 b = 5;
 N = 100;

 f_int1 = integral(f,a,b)
 f_int2 = sum(arrayfun(f,linspace(a,b,N)))*abs(b-a)/N

Try increasing N. Note that you need to sum up small rectangular areas of size f(x)*dx.

Answer 2

[Torsten]

I guess your question aims at the integration of the expression

f = @(T) ( A*(((N0*sin(omega*T).^2.*(1-2*P(T)./k))+(omega.*cos(omega*T) ) ).^2)./(N0.^2*sin (omega*T).^4.*(P(T)-P(T).^2./k).^2) )

from the other thread you opened.

Did you notice that the denominator of your above expression is zero at T=Pi and f thus becomes infinity at this point ?

Best wishes

Torsten.