Mathematics
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OpenStudy (anonymous):
Hi, how do we prove that 3^(2m)*m+3m, is divisible by 4 ?
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ganeshie8 (ganeshie8):
you wanto use congruences / binomial ?
ganeshie8 (ganeshie8):
\(3^{2m}*m + 3m \equiv (-1)^{2m}*m - m \equiv 0 \mod 4\)
OpenStudy (anonymous):
@ganeshie8 Could you explain ?
OpenStudy (anonymous):
Got it
ganeshie8 (ganeshie8):
good :)
just need to see that \(3 \equiv-1 \mod 4\)
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OpenStudy (anonymous):
but how does \((−1)^{2m}∗m−m = 0 mod 4\) ?
ganeshie8 (ganeshie8):
whats the value of \((-1)^{2m}\) after simplifying ?
OpenStudy (anonymous):
OOOOh
ganeshie8 (ganeshie8):
:)
OpenStudy (anonymous):
Exactly
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OpenStudy (anonymous):
What about induction ?
ganeshie8 (ganeshie8):
definitely worth trying ! induction proof looke even more beautiful
OpenStudy (anonymous):
Yes let's get started.
OpenStudy (anonymous):
with \(0\) it's ok.
ganeshie8 (ganeshie8):
yes go straight to induction hypothesis
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OpenStudy (anonymous):
\(m(3^{2m}+3)=0mod4\) is true. :)
OpenStudy (anonymous):
how about, \(m+1(3^{2m}*3+3)\)
OpenStudy (anonymous):
sorry \((m+1)\)
ganeshie8 (ganeshie8):
assume : \(k(3^{2k}+3) = 4n \)
and prove : \((k+1)(3^{2(k+1)}+3) = 4t\)
OpenStudy (anonymous):
Yes
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OpenStudy (anonymous):
@ganeshie8 from where can i find the 4 ?
ganeshie8 (ganeshie8):
its getting nasty lol... @Abhishek619 wana try :)
OpenStudy (anonymous):
It's difficult-
OpenStudy (anonymous):
@ganeshie8 \(-2m=0 mod4\) ?
OpenStudy (anonymous):
induction theorem
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OpenStudy (anonymous):
?
OpenStudy (anonymous):
|dw:1397907875206:dw|
It is divisible by 4.