2 2 votes 1.2 + 2.4 + 3.8 + 4.16 + ----------- k.$2^k$ sum of series ?? i found out its general term but due to $2^k$ iam not able to apply formula ? Mathematical Logic + – sumit goyal 1 2.5k views answer comment Share Follow Print See all 11 Comments 11 11 Comments reply joshi_nitish commented Jan 10, 2018 reply Follow flag is it $2^{k+1}(k-1)+2$ ? 0 0 replyShare Anu007 commented Jan 10, 2018 reply Follow flag this is AP GP series, multiply by 2 then subtract it from given series, you got GP series 1 1 replyShare sumit goyal 1 commented Jan 10, 2018 reply Follow flag @Anu007 thanks when we have AP Gp series we have to always do like this will it work for all questins ?? @joshi_nitish i dont know answer let me now solve 0 0 replyShare Anu007 commented Jan 10, 2018 reply Follow flag yes sumit, nitish i think - 2 will cme. 1 1 replyShare sumit goyal 1 commented Jan 10, 2018 reply Follow flag thnku :) 0 0 replyShare sumit goyal 1 commented Jan 10, 2018 reply Follow flag S = 1.2 + 2.4 + 3.8 + ----- S = 2 + 8 + 24 +--- 2S = 4 + 16 + 48 +--- S-2S = -2 - 8 -24 -------- s = 2 + 8 + 24 +---- hmm where iam wrong iam getting same equation @Anu007 0 0 replyShare joshi_nitish commented Jan 10, 2018 reply Follow flag shift new series(after multiplying by 2) right side by one step, then perform what @Anu sir had said 1 1 replyShare Anu007 commented Jan 10, 2018 reply Follow flag S = 1.21 + 2.22 + 3.23 + ----- 2S = 0+ 1.22 + 2. 23+ 3. 24 etc 1 1 replyShare sumit goyal 1 commented Jan 10, 2018 reply Follow flag @joshi_nitish @ Anu007 got it thanks 0 0 replyShare Mk Utkarsh commented Jan 10, 2018 reply Follow flag S = k2k+1 - 2( 2k -1 ) 1 1 replyShare Mk Utkarsh commented Jan 10, 2018 reply Follow flag ..... 1 1 replyShare Please log in or register to add a comment.