1. The problem statement, all variables and given/known data The technical specification of a particular electrical product states that the probability of its failure with time is given by the function: f(t) = 1 - ke^(-t/t0) if 0 < t < tmax f(t) = 0 if t > tmax where t is the time of service in years, and the constant t0 = 100 years defines the characteristic deterioration time. If the maximal life span of the product tmax is 10 years, find the value of constant k , explaining its meaning, 2. Relevant equations i thought i was supposed to find the integral of 1 - ke^(-t/t0) with respect to t between 0 and 10 years and put the answer equal to 1. then find k from that. 3. The attempt at a solution now this is a past exam paper question so i actually have the partial solution to the question which says that: k = -9/(t0(e^(-10/t0) - 1)) but what i get is k = -9/(t0e^(-10/t0)) I'm pretty sure i'm doing the integral correctly so there must be some step i'm missing that accounts for that extra -1 in the denominator.