PLEASE HELP

Asked by Apoorva | 19th Sep, 2018, 10:04: AM

Expert Answer:

begin mathsize 16px style sum from straight n equals 1 to 11 of space left parenthesis 2 space plus thin space 3 to the power of straight k right parenthesis
equals left parenthesis 2 space plus space 3 right parenthesis thin space plus thin space left parenthesis 2 space plus space 3 squared right parenthesis space plus space left parenthesis 2 space plus thin space 3 cubed right parenthesis space plus space............... plus thin space left parenthesis 2 space plus thin space 3 to the power of 11 right parenthesis
equals left parenthesis 2 space plus space 2 space plus thin space 2...... space 11 space times right parenthesis space plus space left parenthesis 3 space plus thin space 3 squared thin space plus space 3 cubed space plus space.........3 to the power of 11 right parenthesis
equals 2 space cross times space 11 space plus space 3 open parentheses fraction numerator 3 to the power of 11 minus 1 over denominator 3 minus 1 end fraction close parentheses
equals 22 space plus space 3 over 2 open parentheses 3 to the power of 11 minus 1 close parentheses end style

Answered by Sneha shidid | 19th Sep, 2018, 10:59: AM