I notice that in this integration what happened only the variable t
changed to t in the exponential function, is it a rule or something in this type of integration?
I have some confusion with this integral
where exp(...) is the exponential function, the integration from 0 to t, k is a constant (and also t), (t-t) is Dirac delta function which equals 1 when t=t and zero when t≠t
can any one explain to me how this was done?