The singularity functions... doublet, impulse, unit step, unit ramp and unit parabola are used in circut analysis to study circuit response to a disturbance. Integrate in one direction and differentiate in the other... i.e. take the derivative of a ramp and you get a step. Take the derivative of a step and you get an impulse (BTW… the integral of an impulse is = 1). Take the derivative of a impulse and you get a doublet. When you integrate, go in the other direction.