WebMar 22, 2024 · Transcript. 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 …(1) Putting n = 2 in … WebWe know that in an AP sum of the first n terms Sn = (n/2) {2a+ (n-1)d} and the nth term=a+ (n-1)d So (3n/2) {2a+ (3n-1)d} = (n/2) [2 {a+ (3n+1–1)d}+ (n-1)d] =>6a+9nd-3d = 2a+6nd+nd-d.. (This is after cancelling n/2 both sides =>4a+2nd-2d = 0 => 2a+nd-d = 0…. (1) The ratio of the first 2n termsis equal to the sum of the next 2n terms =>
Arithmetic ProgressionIf the sum of the first n terms of an AP is 5n^2 …
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. asked Jul 9, 2024 in Arithmetic Progression by Anaswara (31.5k points) … WebDec 19, 2024 · at n = 1, S 1 = 2 + 3 = 5 = first term at n = 2, S 2 = 2 (2) 2 + 3 (2) = 8 + 6 = 14 ≠ second term = sum of first two terms. ∴ second term = S 2 – S 1 = 14 – 5 = 9 ∴ d = a 2 – … easy fundraising the island n1
The sum of first n terms of an A.P. is 5n n2. Find the nth …
WebMar 23, 2024 · The sum of the third and the seventh terms of an AP is 6 and their product is 8. Find the sum of first sixteen terms of the AP. 3. A ladder has rungs 25 cm apart. (see Fig. 5.7). The rungs decrease uniformly in length from 45 cm at the bottom to 25 cm at the top. WebThe sum of the first n term sofa an AP is ( 3 n 2 2 + 5 n 2). Find its nth term and the 25th term Advertisement Remove all ads Solution Let S denotes the sum of first n terms of the AP. ∴ s n = ( 3 n 2 2 + 5 n 2) ⇒ s n - 1 = 3 ( n - 1) 2 2 + 5 ( n - 1) 2 = 3 ( n 2 - 2 n + 1) 2 + 5 ( n - 1) 2 = 3 n 2 - n - 2 2 ∴ n th term pf the AP , a n WebThe Sum of the First N Terms of an Ap in `((5n^2)/2 + (3n)/2)`.Find Its Nth Term and the 20th Term Of This Ap. CBSE English Medium Class 10 ... Important Solutions 4010. Question Bank Solutions 26519. Concept Notes & Videos 213. Time Tables 14. Syllabus. The Sum of the First N Terms of an Ap in `((5n^2)/2 + (3n)/2)`.Find Its Nth Term and the ... curfew punishment