S
stylz
Member
Hi,
Near the bottom of page 18, Chapter 5, the core reading states that E[X^2] = coefficient of t^2/2! = o^2 + u^2. This is taken from the expansion immediatly preceding.
I don't see how they got this. Which part of the expansion do we use? Is it the whole formula in the brackets? The coefficient seems to me to just be 1/4o^2.
Following on from that I can't work out how they have got E[Z], E[Z^2] etc on the top of the next page (19).
I don't understand what part to use as the coefficient, whether it is just the part in front of t^2 or the whole amount in the brackets.
Can someone enlighten me please.
Cheers
Near the bottom of page 18, Chapter 5, the core reading states that E[X^2] = coefficient of t^2/2! = o^2 + u^2. This is taken from the expansion immediatly preceding.
I don't see how they got this. Which part of the expansion do we use? Is it the whole formula in the brackets? The coefficient seems to me to just be 1/4o^2.
Following on from that I can't work out how they have got E[Z], E[Z^2] etc on the top of the next page (19).
I don't understand what part to use as the coefficient, whether it is just the part in front of t^2 or the whole amount in the brackets.
Can someone enlighten me please.
Cheers