Question

The nth term of a sequence is n²+20

a) Work out the first three terms of the sequence.?
b) How many terms in the sequence are less than 50 ?

Answer 1

a) first three terms are 1^2 + 20 = 21, 2^2 + 20 = 24 and 3^2 + 20 = 29

b) for n^2 + 20 < 50 then n^2 < 30
Only 5 squares are less than 30 ie 1, 4, 9, 16, 25
So five terms in the sequence are less than 50