CBSE Class 10CBSE
Share
Notifications

View all notifications

Find the Sum of the First 13 Terms of the A.P : — 6, 0, 6, 12,.... - CBSE Class 10 - Mathematics

Login
Create free account


      Forgot password?

Question

Find the sum of the first 13 terms of the A.P: -6, 0, 6, 12,....

Solution

In the given problem, we need to find the sum of terms for different arithmetic progressions. So, here we use the following formula for the sum of n terms of an A.P.,

`S_n = n/2 [2a + (n -  1)d]`

Where; a = first term for the given A.P.

d = common difference of the given A.P.

= number of terms

-6, 0, 6, 12,....To 13 terms

Common difference of the A.P. (d) = `a_2 - a_1`

= 0 - (-6)

=  6

Number of terms (n) = 13

First term for the given A.P. (a) = -6

So, using the formula we get,

`S_n = 13/2 [2(-6) + (13 - 1)(6)]`

`= (13/2)[-12 + (12)(6)]`

`= (13/2)[-12 + 72]`

`= (13/2)[60]`

= 390

Therefore, the sum of first 13 terms for the given A.P. is 390

  Is there an error in this question or solution?

APPEARS IN

Solution Find the Sum of the First 13 Terms of the A.P : — 6, 0, 6, 12,.... Concept: Sum of First n Terms of an AP.
S
View in app×