Trailing > Leading P/E?

CFA Level II
#1

Justified leading P/E = (1-b)/(r-g)

Justified trailing P/E = (1+g)(1-b)/(r-g)

I’m not understanding this intuitively, if a company is growing why would last period’s P/E ratio be higher than next period’s P/E ratio?

#2

growing earnings = lower P/E

#3

ahh, that was an easy one

#4

Price is constant at t0 you then calculate pe using the trailing earnings or your projected earnings for the firm.