neha9653
neha9653 neha9653
  • 21-08-2022
  • Mathematics
contestada

11. Find the sum of first 40 terms of an AP whose 2nd term is 2 and 9th term is 37.​

Respuesta :

mmamdouh
mmamdouh mmamdouh
  • 21-08-2022

Answer:

3780

Step-by-step explanation:

First we need to find the common difference (d)

d = (37-2)/7 = 5 (7 jumps from term 2 to term 9)

Second we need to find the first term (a1) using the second term

a1 = 2-5 = -3

Third use the sum formula:

Sn = n/2 x (2a1 +d(n-1))

S40 = 40/2 x (2x-3 + 5(40-1)) = 3780

Answer Link

Otras preguntas

do corrections included prison time, community service, and financial restitution?
Distributive property of 108 with common factors How do you do it
Krishna’s attitude toward Radha can best be described as (A) scornful (B) indiff erent (C) ambivalent (D) coy (E) calculating Passage 2. Jayadeva, Excerpt from
which if the following expressions is equavalent to the expression below 4/7*5/9
Historians have regarded the American Revolution as being of worldwide importance because it
Please answer the question from the attachment.
A ribbon is 12 3/8 feet long.Into how many 3/4-foot pieces can it be cut?
Seeing how strong our gravitational pull is here on Earth, would it be possible to kill someone if you drop a penny off the Empire State building?
An outline of a critical essay is not usually needed. a. True b. False
zach deposits $15,000 into his savings account. his savings account has an annual interest rate of 1.4%. how much money in interest will zach earn if he keeps t