Math, asked by monikashanmugasundar, 4 months ago

Find the sum to 20 terms of the A.P 6,10,14, …..​

Answers

Answered by BrycenCabitac
1

Answer:

a=2

d=6-2=4

n=20

s=n/2[2a+(n-1).d]

s=20/2[2.2+(20-1).4]

s=10[4+(19).4]

s=10[4+76]

s=10[80]

s=10*80

s=800

a = 2

d = 6 - 2 = 4

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

= 20/2 [ 2(2) + 19(4)]

= 10 ( 4 + 76)

= 10 × 80

= 800

Step-by-step explanation:

Answered by akshayakaregama
0
Very simple

As first term of AP is 6 & common difference is 4

We can write general formula for nth term as

Tn = 6 + 4*(n - 1) = 4*n + 2

So 6th term is 4*6 + 2 = 26 &

12th term is 4*12 + 2 = 50

So using summation formula for AP

Sn = n/2 ( first term + last term )

Sum of 7 terms from 6th to twelth is

S7 = 7/2 ( 26 + 50 ) = 7 × 38 = 266



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