Question

Find the 15th term of the sequence 1,2,4,7,11
Find the 12th term of the sequence 2,4,6,8 pls help with d steps.

Answer 1

1,2,4,7,11

It is a pattern wherein 1 consecutive natural numbers are added to subsequent terms'

For example, 1+1=2, 2+2=4, 4+3=7, 7+4=11, 11+5=16 and so on

The bold numbers form the series of natural numbers

Keeping up with the series, we can say that 14 will be added to the 14th term to get the 15th term.

Or in other words, the 15th term is the sum of 1 and the collective sum of first 14 natural numbers

Therefore, 15th term is

      $1+\frac{n(n+1)}{2} =1+\frac{14(14+1)}{2} = 1+7*15 = 106$

      (here n is [15-1]=14)

2,4,6,8.... is the series of even numbers

1st term is 1*2 = 2

2nd term is 2*2 = 4

12th term is 12*2 = 24

HOPE THIS HELPS!!