can anyone please help me to get the inverse Fourier funtion of H(f)

http://upnhanh.sieuthinhanh.com/user...k2yj10638.jpeg

where f is the frequency given in kHz and l is given in meter

I've try many way but still cant solve the problem (Doh)

or is there any possible way to find the value of h(x) at specific "x" using matlab :(?