I have the given expression which is a sum of exponential functions with some parameters $a,t,u,y$ where $a>0$.
Question Is it possible to ask Mathematica to order this expression in terms of descending absolute values of the arguments of the exponential functions? I mean I want that the first term in the desired expression to be the one in which the absolute value of the argument of the exponential function is the largest; then, the next term to be the one with the second largest absolute value of the exponential arguments.
exp = 3816 + 120u E^(2 a) - 1380 E^(4 a) - 50t E^(-(-5 + Sqrt[3]) a) -
300 E^((-1 + Sqrt[3]) a) - 1650 E^(2 (-1 + Sqrt[3]) a) +
360 E^(-(1 + Sqrt[3]) a) + 405 E^(2 (1 + Sqrt[3]) a) +
78 E^((-9 + Sqrt[3]) a) -
75 E^(-2 (-3 + Sqrt[3]) a) (-15 + 8y E^((-3 + Sqrt[3]) a))