First input argument must be a function handle.

Hi, I am trying to integrate using the following function:

if true
syms h g x pi
h = 2.0545
g = 5.3442
C = 1
y = C - (exp(-2.*g.*i.*x./h)).*(C - cos(x).*((h.^2)./2) + (g.*x)/2.*h.*i)
yx = integral(y,-pi,pi)
end

however, I get the error "First input argument must be a function handle. "

Can anyone suggest a solution?

Thanks!

Answer 1

[KSSV]

h = 2.0545 ;
g = 5.3442 ;
C = 1 ;
y = @(x) C - (exp(-2.*g.*1i.*x./h)).*(C - cos(x).*((h.^2)./2) + (g.*x)/2.*h.*1i) ;
yx = integral(y,-pi,pi)

[Sergio Manzetti]

Hi KSSV, tried your suggestion on a full model:

if true
syms h g x C
h = 1.0545;
g = 5.34428;
C = 40;
a = (C - (exp(-2.*g.*i.*x./h)).*(C);
b = (C - (exp(-2.*g.*-i.*x./h)).*(C);
y = @(x) a*b;
q = integral(y,10^-9,0);
end

but it gives:

Error in integral (line 88) Q = integralCalc(fun,a,b,opstruct);

[José-Luis]

 y = @(x) ((C - (exp(-2.*g.*i.*x./h)).*C) * ((C - (exp(-2.*g.*-i.*x./h)).*C);

In your anonymous function the @(x) is not the symbolic variable x.

[Sergio Manzetti]

Thanks. It must have function and not a result or call to another function in other words..?