October 2014 QP: Question 5

How did they calculate the integral while computing Sx?
1. If they are using Uy, why haven't they changed the value to 1/w-y, i.e., in terms of y?
2. Integral of 1/x is log x and not log (1/x). So, how did they arrive at the step in the third line?

 

1. they should.

2. but (integral of -1/x)= - ln(x)= ln(1/x)

 

Got it clear. Thank you so much.

 

I cant understand in this question, how the E(Tx) and E(Tx^2) is calculated? Kindly help understand me.