Formula N(n-1)/2 - General - CodeChef Discuss Trang chủ » Xn = N(n+1)/2 » Formula N(n-1)/2 - General - CodeChef Discuss Có thể bạn quan tâm (x^n)'=nx^n-1 X Noah 2013 Xnor Là Gì Xnow đường Phố Xnpc-7k9b8-y63p8-82mvm-39p2h Loading Formula n(n-1)/2 general math-formulas ramher237 February 19, 2015, 7:29am 1 I know that n(n+1)/2 is getting the sum of 1 to n numbers. How about the n(n-1)/2? where and when do we use this formula? and what other formulas are related to these two? 7 Likes betlista February 19, 2015, 9:36am 2 I’d say, that if \frac{n(n+1)}{2} is som of n numbers, then \frac{(n-1)n}{2} is the sum of n-1 numbers, do you agree? You know, it’s not easy to answer the question without the proper context… Second formula can also be used to find out number of combinations how to choose two elements out of n, or how many elements Ai,j are in square matrix where i < j and probably one can find another dozen of descriptions… 23 Likes arun_as February 19, 2015, 10:12am 3 As @betlista has said, n(n-1)/2 is the sum of the first (n-1) numbers, that is 1 + 2 + 3 + 4 + .......... + (n-1) Now one might think that there is not much use for this formula, but when you do some research, you can find interesting uses for it. @betlista has explained a few uses. Here is a link which explains one usage link 4 Likes futuregoal September 14, 2020, 6:47am 4 So basically it is a combination formula where you need to choose r element out of n and order does not matter. n * (n-1) / 2 Same as NCR forumula which is N! / (N-R)! * R! 10 Likes rude009 September 14, 2020, 9:57am 5 Bruh its been six years 7 Likes tle_25 September 14, 2020, 10:05am 6 Legend says he is still asking this question. Duhhhh 12 Likes anon9296580 February 7, 2021, 1:23pm 7 Your answer is right , if you look at T(n) for insertion sort here you can see how outer loop runs for n(n+1)/2 -1 times and inner while runs one less than test case which again yields (n-1)(n-1+1)/2=n(n-1)/2 logesh7101998 February 9, 2021, 3:16am 8 (n + 1) * (n + 2)/ 2 are both are same n*(n + 1) / 2 can anyone explain? onlykingkd February 9, 2021, 3:54am 9 n*(n-1)/2 .This formula is mostly used to find total number of subarrays for a given array of size n 2 Likes suman_18733097 February 9, 2021, 3:59am 10 onlykingkd: n*(n-1)/2 .This formula is mostly used to find total number of subarrays for a given array of size n I think it should have been \frac{n\times (n+1)}{2}. You missed subarrays of size 1. 2 Likes rishikr February 9, 2021, 4:30am 11 nC2 ->Combination, number of handshakes 3 Likes zephxr February 9, 2021, 4:52am 12 This link is not working. therealnishuz February 9, 2021, 7:28am 13 It was posted in 2015 4 Likes logesh7101998 February 9, 2021, 11:38am 14 use n as 5 it give sum of n number n*(n+1)/2 = 5(5+1)/2=15 it give sum of n+1 number (n+1)(n+2)/2 =(67)/2=31 it give sum of n-1 number n*(n-1)/2 = 5(5-1)/2=10 it give sum of square n2 n(n+1)(2n+1)/6 = 5(6)(11)/6=55 it give sum of cube n3 [ n*(n-1)/2]2 =( 5(5-1)/2)2=100 2 Likes ryan_mitchell February 10, 2022, 7:46am 16 There are a lot of good answers here, I think he found the answer to his question 1 Like exmuslimsahi July 15, 2023, 9:53am 18 Gosh maths is not for me,send me to stone age that’s where i belong. Từ khóa » Xn = N(n+1)/2 Why Does A Triangular Sequence Use This Formula Xn = N(n+1) /2? Proof That T(n)=n(n+1)/2 Sequences - Finding A Rule - Math Is Fun [PDF] The Normal Distribution [PDF] The Limit Of A Sequence - MIT Mathematics Binomial Theorem - Wikipedia [PDF] MATHEMATICAL INDUCTION SEQUENCES And SERIES [PDF] Tests For Convergence Of Series 1) Use The Comparison Test To ... [PDF] Introduction To The Convergence Of Sequences [PDF] Lectures 11 - 13 : Infinite Series, Convergence Tests, Leibniz's Theorem [PDF] §11.8 3-20 Find The Radius Of Convergence And Interval Of ... [PDF] Sigma Notation - The University Of Sydney [PDF] Sample Induction Proofs - Math
