- #1
javi438
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proof for inequality induction...please help!
Prove for all positive integers n that
[tex]\sum^{n}_{l=1} l^{-1/2} > 2(\sqrt{n+1} -1)[/tex]
2. The attempt at a solution
[tex]\sum^{n+1}_{l=1} l^{-1/2}
= \sum^{n}_{l=1} l^{-1/2} + (n+1)^{-1/2} > 2(\sqrt{n+1} -1) + (n+1)^{-1/2} [/tex]
please help meee! I'm getting stuck, on how to express [tex] 2(\sqrt{n+1} -1) + (n+1)^{-1/2} [/tex] in terms of [tex] 2(\sqrt{n+2} -1) [/tex]
Homework Statement
Prove for all positive integers n that
[tex]\sum^{n}_{l=1} l^{-1/2} > 2(\sqrt{n+1} -1)[/tex]
2. The attempt at a solution
[tex]\sum^{n+1}_{l=1} l^{-1/2}
= \sum^{n}_{l=1} l^{-1/2} + (n+1)^{-1/2} > 2(\sqrt{n+1} -1) + (n+1)^{-1/2} [/tex]
please help meee! I'm getting stuck, on how to express [tex] 2(\sqrt{n+1} -1) + (n+1)^{-1/2} [/tex] in terms of [tex] 2(\sqrt{n+2} -1) [/tex]
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