Question

If the first term of an AP is –5 and the common difference is 2, then the sum of the first 6 terms is ______.

विकल्प

• 0

• 5

• 6

• 15

Answer 1

If the first term of an AP is –5 and the common difference is 2, then the sum of the first 6 terms is 0.

Explanation:

Given,

a = –5

And d = 2

∴ S₆ = `6/2[2a + (6 - 1)d]`  ...`[∵  S_n = n/2[2a + (n - 1)d]]`

= 3[2(–5) + 5(2)]

= 3(–10 + 10)

= 0