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Let `S=Sigma_(n=1)^(999) (1)/((sqrt(n)+sqrt(n+1))(4sqrt(n)+4sqrtn+1))` , then S equals ___________. |
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Answer» Correct Answer - 9 Given `S=sum_(n=1)^(9999)1/((sqrtn+sqrn(n+1)(root4n+root(4)(n+1)))` `=sum_(n=1)^(9999)1/((sqrtn+sqrt(n+1))(root4n+root(4)(n+1)))((root4n-root(4)(n+1))/(root4n-root(4)(n+1)))` `=sum_(n=1)^(9999)((n+1)^(1//4)-n^(1//4))` `=((2^(1/4)-1)+(3^(1/4)-2^(1/4))+(4^(1/4)-3^(1/4))+....+((9999+1)^(1/4)-(9999)^(1/4)))` `=(10^(4))^(1/4)-1` =9 |
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