Let the probability of event a be p = P (a). Now repeat the experiment n times independently, and try to find the probability of a appearing at least once

Let the probability of event a be p = P (a). Now repeat the experiment n times independently, and try to find the probability of a appearing at least once

Using indirect method, the probability of not appearing once is (1-p) ^ n, so the probability of appearing at least once is 1 - (1-p) ^ n