how to find the integral of F = x./(1+x.^4) on matlab

how to find the integral of F = x./(1+x.^4) on matlab in the range of 0 and 5 i have used the following; int(F,x,0,6)

but an error of "Undefined function 'int' for input arguments of type 'double'." comes up.

[Roger Stafford]

Note that this a problem you don't really need matlab for. A calculus student would tell you to substitute y = x^2 to produce the integral of 1/2/(1+y^2) with respect to y from y = 0 to y = 6^2 which gives you 1/2*atan(36).

Answer 1

[Star Strider]

Use the integral function:

F = @(x) x./(1+x.^4) 
C = integral(F, 0, 6)

produces:

C =

     771.5128e-003

Answer 2

[John D'Errico]

IF you have the symbolic toolbox, then do this:

syms x
int(x/(1+x^4),x,0,6)
ans =
atan(36)/2

If not, then do it numerically.

format long g
integral(@(x) x./(1 + x.^4),0,6)
ans =
         0.771512845100738

Note that the numerical solution happens to match the symbolic one. A good thing, really.

atan(36)/2
ans =
         0.771512845100738