Question

If the nth term of an AP is given as a_{​​​​​​n}= 5-11n. Find the common difference.

Answer 1

Here,

an = 5 – 11n ------------- (1)

Taking n = 1 in eqⁿ (1), we get

➡ a1 = 5 – 11(1)

➡ a1 = 5 – 11

➡ a1 = –6

Now, Taking n = 2 in eqⁿ (1), we get

➡ a2 = 5 – 11(2)

➡ a2 = 5 – 22

➡ a2 = – 17

Now, Taking n = 3 in eqⁿ (1), we get

➡ a3 = 5 – 11(3)

➡ a3 = 5 – 33

➡ a3 = – 28

Now, we get the AP :-

–6, – 17, – 28,..........

Here, the common difference is

➡ d = –17 – (–6)

➡ d = –17 + 6

➡ d = –11