Q10 of 178 Page 548

What is the 5th term from the end of the AP 2, 7, 12, ..., 47?

Here, First term = a = 2

Common difference = d = 7 - 2 = 5

Last term = l = 47

To find:5^th term from end.

So, n^th term from end is given by:

a_n = l - (n - 1)d

∴ 5^th term from end is:

a₅ = 47 - (5 - 1) × 5

= 47 - 20

= 27

∴ 5^th term from the end is 27.

If the sum of first m terms of an AP is (2m² + 3m) then what is its second term?

What is the sum of first n terms of the AP a, 3a, 5a, ....

If a_n denotes the nth term of the AP 2, 7, 12, 17, ..., find the value of (a₃₀ – a₂₀).

The n^th term of an AP is (3n + 5). Find its common difference.