Question

The sum of first 15 term arithmetic sequence is 570 and 12th term is 62 write its sequence

Answer 1

Answer:

which lesson mentioned any thing

Answer 2

Answer:

Sequence :     -4, 2 , 8 , 14, 20, 26, 32, 38, 44, 50, 56, 62 ....

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Step-by-step explanation:

Nth term = a + ( n - 1) d

12th term = a + ( 12 - 1) d

⇒ a + 11d = 62 [Given]

⇒ a = 62 - 11d

Sum of Nterms = $\frac{n}{2}[2a + (n-1)d]$

Sum of 15 terms = $\frac{15}{2}[2a + (15-1)d] = 570$

⇒ 2a + 14d = 76

Keeping the value of a in the given equation :

⇒ 2(62 - 11d) + 14d = 76

⇒ 124 - 22d + 14d = 76

⇒ 124 - 76 = 22d - 14d

⇒ 48 = 8d

⇒ d = 48/8 = 6

⇒ d = 6

∵ a = 62 - 11d

⇒ a = 62 - 11 × 6

⇒ a = 62 - 66

⇒ a = -4

∴ Sequence :     -4, 2 , 8 , 14, 20, 26, 32, 38, 44, 50, 56, 62 ....