in an AP the first term is -8 and the last term is 100 find the sum of its first 20 terms
need correct answer!!!
Answers
Answered by
2
Answer:
A Variable is a symbol for a number we don't know yet. It is usually a letter like x or y.
A number on its own is called a Constant.
A Coefficient is a number used to multiply a variable (4x means 4 times x, so 4 is a coefficient)
Variables on their own (without a number next to them) actually have a coefficient of 1 (x is really 1x)
Sometimes a coefficient is a letter like a or b instead of a number:
Answered by
1
Answer:
Given, a = 100, d = -2, tn = -10 Using, tn = a + (n - 1)d -10 = 100 + (n - 1)(-2) -10 = 100 - 2n + 2 2n = 100 + 2 + 10 2n = 112 n = 112/2 n = 56 Here 56th term is -10 Number of terms in A.P. are 56 Sn = n/2(a + l) S56 = 56/2 (100 - 10) = 28 x 90 = 2520Read more on Sarthaks.com - https://www.sarthaks.com/569585/the-common-difference-of-an-a-p-is-2-find-its-sum-if-its-first-term-is-100-and-the-last-term-is-10
Similar questions