are you sure about that first formula? Cause:
(1+r)^n/(1+r)^(n-1) is the same as 1+r
there for:
y=r*G*(1+r)^n/(1+r)^n-1
is the same as
y= (r*G*(1+r))
So it seems strange to me if your teacher would give you that formula, when the formula is just crap. That's like saying: I'm 21+1-1 years old.
(1+r)^n/(1+r)^(n-1) is the same as 1+r
there for:
y=r*G*(1+r)^n/(1+r)^n-1
is the same as
y= (r*G*(1+r))
So it seems strange to me if your teacher would give you that formula, when the formula is just crap. That's like saying: I'm 21+1-1 years old.