Question

explain fourier integral?

Answer 1

of course, not all functions are -periodic and it may be impossible to represent a function definedon, say, all of by a Fourier series. ... Fortunately, under suitable conditions, a function can be represented as an integral as the following theorem known as theFourier Integral Theorem states.

Answer 2

fourier intergal are the genralizations of fourier series .
The series represention f a function is a periodic form by obtained by generating the coffecients from the function definition on the least period (-L,L)