Web22 Mar 2024 · Ex 9.2,13 If the sum of n terms of an A.P. is 3n2 + 5n and its mth term is 164, find the value of m. Let a1, a2, … an be the given A.P Given, Sum of n terms = 3n2 + 5n Sn = 3n2 + 5n Putting n = 1 in (1) S1 = 3 × 12 + 5 × 1 = 3 × 1 + 5 × 1 = 3 + 5 = 8 Sum of first 1 terms = First term ∴ First term = a1 = S1 = 8 Sn = 3n2 + 5n … WebComputation is done every year to know the interest earned. The first interest is added to the deposit. This sum also earns interest for the next period.12. At the start of an experiment, there are 2000 bacteria in a colony. In 2 hours, the population has tripled. Assume that the growth law N = N0ekt applies. Determine ek13.
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WebThe sum of n terms of an AP can be found using one of the following formulas: S n = n/2 (2a+ (n−1)d) S n = n/2 (a 1 +a n) Here, a = a 1 = the first term, d = the common difference, n = number of terms, a n = n th term, S n = the sum of the first n terms. What is the Commonly Used Sum of AP Formula? WebThe sum of the first n terms of an AP is (5n 2 /2 +3n/2). Find its nth term and the 20th term of this AP. arithmetic progression class-10 1 Answer +2 votes answered Sep 14, 2024 by … customer whiteboard
Factor 3n^2+5n+2 Mathway
WebQ8. If the ratio of sum of the first m and n terms of an AP is m2 : n2, show that the ratio of its mth and nth terms is (2m – 1) : (2n – 1). Q9. If m times mth term of an AP is equal to n times nth term, find the (m + n)th term of the AP. Q10. The sum of the first 7 terms of an AP is 63 and the sum of its next 7 terms is 161. Web7 Apr 2024 · Hence, the sum of the first 15 terms of given A.P. is 525. (ii) b n = 5 + 2n Solution: Given A.P. has nth term, a n = 5 + 2n and number of terms (n) = 15 So, a n = 5 + 2 (15) = 35 On putting n = 1, we get a, first term of the A.P., a = 5 + 2 (1) = 7 S 15 = n [a + a n ]/2 = 15 (7 + 35)/2 = 15 x 21 = 315 Web27 Dec 2012 · Sum of first n terms of AP, S n = 2n 2 + 5n Now choose n =1 and put in the above formula, First term = 2+5 = 7 . Now put n=2 to get the sum of first two terms = 2x4 + 5x 2= 8 + 10 = 18 . This means . first term + second term = 18 . but first term =7 as calculated above . so, second term = 18-7 = 11 . chatgpt australian government