Selection round 2019 Mymensingh Higher Secondary #6

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samiul_samin
Posts:1007
Joined:Sat Dec 09, 2017 1:32 pm
Selection round 2019 Mymensingh Higher Secondary #6

Unread post by samiul_samin » Wed Jan 30, 2019 2:27 pm

$f(3n)=3f(n)$
$f(3n+1)=3f(n)-1$
$f(3n+2)=3f(n)-2$
$f(1)=1$ $f(2)=1$
$f(1009)$=?
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samiul_samin
Posts:1007
Joined:Sat Dec 09, 2017 1:32 pm

Re: Selection round 2019 Mymensingh Higher Secondary #6

Unread post by samiul_samin » Wed Jan 30, 2019 3:23 pm

hint
Recursive function
Answer
$449$
Sol^n

$f(1009)=f(3×336+1)=3f(336)-1=3f(3×112)-1=9f(112)-1=9f(37×3+1)-1=9{3f(37-1)}-1=27f(37)-10=27f(3×12+1)-10=81f(12)-27-10=3×81f(4)-37=243f(3×1+1)-37=243{3f(1)-1}-37=243×{3x1-1}-37=243×2-37=449$
Question reapeted from moulovibazar regional $2017$ .
Note
Post no $500$
Most of them are useless :cry: :cry: :cry: :cry: :cry:
No way to delete them!!! :?: :?: :?: :?: :?: :?:
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