Induction with two unknown variables












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$begingroup$


I have been at this problem for a while now, and I cannot wrap my head around it. Any kind of help would be greatly appreciated!



The runtime for a sorting algorithm can be described by $a_{1} = 3$ and



enter image description here



I need to prove, that



enter image description here



For all $n, k in Z^{+}$



I've tried to do the basestep, but even here I'm not sure if it's correct. I hope someone can help with the induction step as well.



Basecase:



$n, k = 2$



$a_{2} =a_{2/2} + a_{2/2} + 3*2+1 = 13 $



$3* 2 * 2^2 + 4 * 2^2 -1 = 39$



$a_n leq 3 * k * 2^k + 4 * 2^k - 1$ applies for the basebase, since $13 leq 39$ is true.



Inductionstep:



?










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  • $begingroup$
    We just saw this one, but I can't find the duplicate.
    $endgroup$
    – Ross Millikan
    Jan 7 at 15:05










  • $begingroup$
    You just need to induct on $k$. The base case should be $k=1$ Then note that $nle2^kimpliesleftlceil{ nover2}rightrceille2^{k-1}$
    $endgroup$
    – saulspatz
    Jan 7 at 15:16


















0












$begingroup$


I have been at this problem for a while now, and I cannot wrap my head around it. Any kind of help would be greatly appreciated!



The runtime for a sorting algorithm can be described by $a_{1} = 3$ and



enter image description here



I need to prove, that



enter image description here



For all $n, k in Z^{+}$



I've tried to do the basestep, but even here I'm not sure if it's correct. I hope someone can help with the induction step as well.



Basecase:



$n, k = 2$



$a_{2} =a_{2/2} + a_{2/2} + 3*2+1 = 13 $



$3* 2 * 2^2 + 4 * 2^2 -1 = 39$



$a_n leq 3 * k * 2^k + 4 * 2^k - 1$ applies for the basebase, since $13 leq 39$ is true.



Inductionstep:



?










share|cite|improve this question









$endgroup$












  • $begingroup$
    We just saw this one, but I can't find the duplicate.
    $endgroup$
    – Ross Millikan
    Jan 7 at 15:05










  • $begingroup$
    You just need to induct on $k$. The base case should be $k=1$ Then note that $nle2^kimpliesleftlceil{ nover2}rightrceille2^{k-1}$
    $endgroup$
    – saulspatz
    Jan 7 at 15:16
















0












0








0





$begingroup$


I have been at this problem for a while now, and I cannot wrap my head around it. Any kind of help would be greatly appreciated!



The runtime for a sorting algorithm can be described by $a_{1} = 3$ and



enter image description here



I need to prove, that



enter image description here



For all $n, k in Z^{+}$



I've tried to do the basestep, but even here I'm not sure if it's correct. I hope someone can help with the induction step as well.



Basecase:



$n, k = 2$



$a_{2} =a_{2/2} + a_{2/2} + 3*2+1 = 13 $



$3* 2 * 2^2 + 4 * 2^2 -1 = 39$



$a_n leq 3 * k * 2^k + 4 * 2^k - 1$ applies for the basebase, since $13 leq 39$ is true.



Inductionstep:



?










share|cite|improve this question









$endgroup$




I have been at this problem for a while now, and I cannot wrap my head around it. Any kind of help would be greatly appreciated!



The runtime for a sorting algorithm can be described by $a_{1} = 3$ and



enter image description here



I need to prove, that



enter image description here



For all $n, k in Z^{+}$



I've tried to do the basestep, but even here I'm not sure if it's correct. I hope someone can help with the induction step as well.



Basecase:



$n, k = 2$



$a_{2} =a_{2/2} + a_{2/2} + 3*2+1 = 13 $



$3* 2 * 2^2 + 4 * 2^2 -1 = 39$



$a_n leq 3 * k * 2^k + 4 * 2^k - 1$ applies for the basebase, since $13 leq 39$ is true.



Inductionstep:



?







induction






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asked Jan 7 at 14:39









jubibannajubibanna

1293




1293












  • $begingroup$
    We just saw this one, but I can't find the duplicate.
    $endgroup$
    – Ross Millikan
    Jan 7 at 15:05










  • $begingroup$
    You just need to induct on $k$. The base case should be $k=1$ Then note that $nle2^kimpliesleftlceil{ nover2}rightrceille2^{k-1}$
    $endgroup$
    – saulspatz
    Jan 7 at 15:16




















  • $begingroup$
    We just saw this one, but I can't find the duplicate.
    $endgroup$
    – Ross Millikan
    Jan 7 at 15:05










  • $begingroup$
    You just need to induct on $k$. The base case should be $k=1$ Then note that $nle2^kimpliesleftlceil{ nover2}rightrceille2^{k-1}$
    $endgroup$
    – saulspatz
    Jan 7 at 15:16


















$begingroup$
We just saw this one, but I can't find the duplicate.
$endgroup$
– Ross Millikan
Jan 7 at 15:05




$begingroup$
We just saw this one, but I can't find the duplicate.
$endgroup$
– Ross Millikan
Jan 7 at 15:05












$begingroup$
You just need to induct on $k$. The base case should be $k=1$ Then note that $nle2^kimpliesleftlceil{ nover2}rightrceille2^{k-1}$
$endgroup$
– saulspatz
Jan 7 at 15:16






$begingroup$
You just need to induct on $k$. The base case should be $k=1$ Then note that $nle2^kimpliesleftlceil{ nover2}rightrceille2^{k-1}$
$endgroup$
– saulspatz
Jan 7 at 15:16












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Try to prove by induction over $k$ that for all $1 leq n leq 2^k$, $a_n leq 3k2^k+2^{k+2}-1$.






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    $begingroup$

    Try to prove by induction over $k$ that for all $1 leq n leq 2^k$, $a_n leq 3k2^k+2^{k+2}-1$.






    share|cite|improve this answer









    $endgroup$


















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      $begingroup$

      Try to prove by induction over $k$ that for all $1 leq n leq 2^k$, $a_n leq 3k2^k+2^{k+2}-1$.






      share|cite|improve this answer









      $endgroup$
















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        $begingroup$

        Try to prove by induction over $k$ that for all $1 leq n leq 2^k$, $a_n leq 3k2^k+2^{k+2}-1$.






        share|cite|improve this answer









        $endgroup$



        Try to prove by induction over $k$ that for all $1 leq n leq 2^k$, $a_n leq 3k2^k+2^{k+2}-1$.







        share|cite|improve this answer












        share|cite|improve this answer



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        answered Jan 7 at 14:47









        MindlackMindlack

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        4,910211






























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