WebNov 11, 2011 · Find the sum of first n terms if an AP whose nth term is 5n-1. Hence find the sum of first 20 terms Asked by 11 Nov, 2011, 04:16: PM Expert Answer n th term = 5n - 1 Put n=1, we get 1 st term = 5-1 = 4 Hence sum of n terms = n (First term + nth term)/2 = n (4+5n - 1)/2 = n (5n +3)/2 Sum of 20 terms becomes, put n = 20 S 20 = 20 (5×20 +3)/2 WebThe sum of the first n terms of an AP in ( 5 n 2 2 + 3 n 2) .Find its nth term and the 20th term of this AP. Advertisement Remove all ads Solution s n = ( 5 n 2 2 + 3 n 2) = 1 2 ( 5 n 2 + 3 n) ..... (1) Replacing n by (n-1) in (i), we get: s n - 1 = 1 2 × [ 5 ( n - 1) 2 + 3 ( n - 1)] = 1 2 × [ 5 n 2 - 10 n + 5 + 3 n - 3] = 1 2 × [ 5 n 2 - 7 n + 2]
The Sum of the First N Term Sofa an Ap is ` ( (3n^2) /2 + (5n) /2 ...
Web(11) Search the sum the first 20 terms of the numerical series in which 3 rl term is 7 also 7 in term is 2 more than three time its 3 rad term. Solution (12) Stylish an arithmetic series, which sum of first 11 conditions is 44 and one that of the next 11 terms is 55. WebSolution Given that sum of the first n terms of an AP is 5n - n 2 Sn = 5n − n 2 First term, a 1 = S 1 = 5 (1) − (1) 2 = 5 − 1 = 4 Sum of first two terms = S 2 = 5 (2) − (2) 2 = 10 − 4 = 6. … grape allergic reaction
Arithmetic Progression-Definition, Nth Term, Formulas, Sum
WebJun 22, 2024 · According to the given problem The ratio of the sums of first n terms of two A.P.s = (5n+13) : (7n +27 ) = (5n+13) / (7n +27 ) --------------- (4) (3) and (4) are equal. => [2a+ (n-1)d]/ [2b+ (n-1)c] = (5n+13)/ (7n+27) To find ratio of 4 terms , write n = 7 since (2×4-1)=7 => [2a+ (7-1)d]/ [2b+ (7-1)c]= (5 (7)+13))/ (7 (7)+27)) 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) … WebAnswer (1 of 3): If a is initial term & d is the common difference, then Sn = { 2a + ( n - 1 ) *d } * n/2 So S2n = { 2a + ( 2n - 1) *d } * n = 2an + 2n^2d - nd = (2a -d)n + 2n^2d = 3n + 14 n^2 Comparing coefficients with terms of n & n^2 we observe 2a - … grape analytics