I worked out this question but my answer does not match with the one given in the indicative solution. It is written that (E_x)^c can be approximated as (summation from 0 to N-1)(Px(t+(1/2)). What I cannot understand is that why can't we simply use the trapezium formula given in the CT4 Notes? Also, please confirm, we have 3 values of Px(t) provided- Px(1/2), Px(1(1/2)) and P(2(1/2)) right? Kindly help. Thanks