Final answer:
The limit is expressed as a definite integral by taking the limit as AQi approaches 0 and the number of steps approaches infinity. The integral is broken into three parts: negative infinity to zero, zero to L, and L to infinity. The first and last integrals are zero, resulting in the given integral equation.
Step-by-step explanation:
The limit is expressed as a definite integral by taking the limit as AQi approaches 0 and the number of steps approaches infinity. This is done by replacing the summation with an integral. The integral is broken into three parts: negative infinity to zero, zero to L, and L to infinity. Due to the constraints of the problem, the first and last integrals are zero, resulting in the integral equation given.