Romeo and juliet have a date at a given time, and each, independently, will be late by an amount of time that is exponentially distributed with parameter λ. what is the probability density function of the difference (just the difference, not the absolute difference, so it can be negative if romeo comes early) between romeo’s and juliet’s arrival time?

Ithink the answer is c

First step is to get rid of the square root. remember that a square root is the same as raising to the (1/2) power. see below: multiply exponents per exponent rules to get: remember you subtract exponents from the denominator and add exponents in the numerator so: simplify further: so a is the correct choice. if you don't understand this google exponent rules and it will you understand. look at the image results.