1. A sequence is defined byf(0)=-20, f(n)=f(n-1)-5 for n>1 . Explain why f(1)=-20-5

Answer 1

If f(0) = -20 and

f(n) = f(n-1) - 5

then f(1) = -20 - 5

When you look at f(1), then the n in f(n) is equal to 1.

Therefore n-1 = 1-1 = 0

So f(1) = f(0) - 5

and since f(0) = -20

then f(1) = -20-5 = -25