Question: prove by induction 2^2 + 4^2 + 6^2 + ... + (2n)^2 = (2n)(2n+1)(2n+2)/6 ANSWER we will use induction on n base case : n=1 we have, 2^2 = 2*3*4/6 = 4 which is true inductive hypothesis let it be true for n = k i.e., 2^2 + 4^2 + ... + (2k)^2 = [(2k)(2k+1)(2k+2)]/6 inductive case let n = k+1 then we have 2^2 + 4^2 + .... + (2k)^2 + (2(k+1))^2 = [(2k)(2k+1)(2k+2)]/6 + (2k+2)^2 =(2k+2)*[(2k)(2k+1)/6 + (2k+2)] =(2k+2)*[ (4k^2+2k)/6 + (12k + 12)/6 ] =(2k+2)*[ (4k^2+14k+12)/6 ] = =(2k+2)*[(2k)(2k+1)/6 + (2k+2)] =(2k+2)*[ (4k^2+2k)/6 + (12k + 12)/6 ] =(2k+2)*[ (4k^2+14k+12)/6 ] = (2k+2)*[ (4k^2 + 8k + 6k + 12)/6 ] = (2k+2)*[ (4k(k + 2) +6(k+2))/6 ] = (2k+2)*[ (4k+6)(k+2)/6 ] = (2k+2)*[ 2 (2k+3)(k+2)/6 ] = (2k+2)*[ (2k+3)*2*(k+2)/6 ] = (2k+2)*[ (2k+3)(2k+4)/6 ] = [(2*(k+1))(2*(k+1)+1)(2*(k+1)+2)]/6 replacing k+1 by m, we get replacing k+1 by m, we get [(2*m)(2*m+1)(2*m+2)]/6 this completes our proof b...





![\mu = E[Xi]](https://media.cheggcdn.com/media%2F5c1%2F5c13f0d5-1757-45ac-9857-bc69eed05969%2F23e19639-6952-4d66-bf9f-f7d729324c19.gif)
![\sigma ^{^{2}} = V[Xi]](https://media.cheggcdn.com/media%2Fefe%2Fefe14016-3141-4d72-96cf-27b29916f73f%2Ff550f675-c2a4-4c1d-ba3a-14fddca040f4.gif)

![X \xrightarrow[n\rightarrow \infty]{d } N (n\mu ,n\sigma ^{2})](https://media.cheggcdn.com/media%2F366%2F366caba8-10e5-470d-8b3a-f6c636f93e8d%2Ff624942f-99dd-4877-a6c5-f23965dc45e2.gif)
![E[X] = n\mu](https://media.cheggcdn.com/media%2Fd31%2Fd3107007-00b2-4af1-baef-e8daecf36d4f%2F20e7d089-8dd0-4902-a347-a3066a2d5639.gif)
![V[X] = \sigma{\sqrt{}}n](https://media.cheggcdn.com/media%2Fe90%2Fe907fa54-0914-48d4-9b30-9bcfb3ec06ae%2F04bbfa80-e633-4e1d-ba4f-daa67d3bc142.gif)
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