Integration variable inside interpolation function

Hi all,

I wish to perform an integration as indicated below.

I am facing an error because the I am using the integration variable 'u' inside interpolation function. (If I replace 'u' inside interpolation function by some constant, the integration runs fine.)

>> syms u
>> double(int(2*interp1(x,y,u),u,0,0.1))
Error using interp1>Interp1D (line 330)
Inputs must be floats, namely single or double.

Error in interp1 (line 220)
    Vq = Interp1D(X,V,Xq,method);

Can you please provide some pointers to fix it.

P.S.: For clarification, y=f(x) [piecewise function] which is why I am interpolating to determine intermediate values.

Thanks a lot !!

Answer 1

[Matt J]

Why do it by symbolic computation at all? Why not just use integral() or trapz()?