Hello my friend from Pakistan, I think I can help you with your linear system task, I'm on my 4th year graduation in electrical engineering, so I've been passed through all the courses about Fourier Series, Laplace transform and Fourier transform. I already done courses like Signals and Systems, Linear Systems Control and Signal Processing, so I'm very comfortable in work with Fourier problems. If you see that I'm the right person to work with you, talk to me. Hope to hear from you soon! Cheers!