Help me with a proof syntax in Probabilities, min() in R.Vs

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Given U,V independent exponential R.Vs. Find the law of min(U,V).

I understand some of the basics, but I need exact formal proof at the beginning since I've seen very few of these questions. I will write the beginning which I hesitate of. Could you correct my mistakes? Or approve my 100% correctness.

My solution:

U and V are Random Variables. Thus we are looking for

$P\{\{t<U\} \bigcap \{t<V\}\}$

U, V are independent. Hence

$=P\{t<U\}\bigcap P\{t<V\}$

Which is in turn:

$=F_U(t)F_V(t)$

And then we calculate and differentiate.

Did I write it wrong somewhere? Is everything correct?