Question

Find The Sum of first 13 terms
the AP -6,0 6,​

Answer 1

Answer:

Sn = n2n2[2a + (n − 1)d]

Where; a = first term for the given A.P. d = common difference of the given A.P. n = number of terms

Given A.P. – 6, 0, 6, 12, … to 13 terms.

Common difference (d) = a2 – a1 = 6 – 0 = 6

Number of terms (n) = 13

First term (a) = -6

So,

S13  = 132132[2(− 6) + (13 –1)6]

= 132132[(−12) + (12)6]

= 132132[60]

= 390

Hence, the sum of first 13 terms for the given A.P. is 390Read more on Sarthaks.com - https://www.sarthaks.com/655065/find-the-sum-of-the-first-13-terms-of-the-a-p-6-0-6-12

Step-by-step explanation:

Answer 2

Answer:

390

Step-by-step explanation:

a=-6 d=6

Sn=n/2[2a+(n-1)d

S13=13/2[2(-6)+(13-1)6]

S13=13/2[-12+(12)6]

S13=13/2[-12+72]

S13=13/2[60]

S13=13(30)

S13=390