Question

Find the nth term and the 12th term of the list of numbers: 5, 2, – 1, – 4, …

Answer 1

5, 2, -1, -4, …
Here, a = 5 d = 2 – 5 = -3
(i) T_n = a + (n – 1)d
= 5 + (n – 1) (-3)
= 5 – 3n + 3
= 8 – 3n
(ii) T₁₂ = a + 11d
= 5 + 11(-3)
= 5 – 33
= -28