Amachineworksforanexponentiallydist ributedtimewithrateμandthenfails. a repair crew checks the machine at times distributed according to a poisson process with rate λ; if the machine is found to have failed then it is immediately replaced. find the expected time between replacements of machines.
the length of the minor arc = circumference × fraction of circle
arc ab = 2π × 10 ×
= 20π × = 5π ≈ 15.7 cm → b