marginal distribution when integration bounds include infinity

[@andrejgrebenc3235]

A bit clumsy with integral 2*exp(-x-2*y). It is 2*exp(-x) * integral exp(-2*y)*dy

[@Stats4Everyone]

Thanks for the comment Andrej. It is true that I could have included your step, though I would arrive at the same answer. Please watch the video here for more expatiation: kzbin.info/www/bejne/bZnZZKqkq9OIadU