Mathematics
12 Online
OpenStudy (anonymous):
Discrete Mathematics paths help. Picture provided.
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OpenStudy (anonymous):
ganeshie8 (ganeshie8):
@dan815
OpenStudy (dan815):
game of choosing
OpenStudy (dan815):
a certain number of east and a certain number o north
OpenStudy (dan815):
are required to travel your path so
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OpenStudy (dan815):
its how many ways you can choose the c1 Norths and c2 Easts
ganeshie8 (ganeshie8):
(n-1) norths and (n-1) easts ?
OpenStudy (dan815):
or i should say i Easts and j norths
OpenStudy (dan815):
yeah from 1,1 so it should be picking n-2 Norhs and n-2 Easts right?
OpenStudy (dan815):
choosing*
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OpenStudy (anonymous):
I'm a bit confused on how that would look equation wise. Or can it be put into an equation?
OpenStudy (dan815):
oh sry wait i was just answering that thought in their question where they want to go from
1,1 to (n-1,n-1)
OpenStudy (anonymous):
Are you talking about part a?
OpenStudy (dan815):
is a asking if we are i,j... how many ways are there to reach n-1,n-1?
OpenStudy (dan815):
that would be
(n-1-i) east and (n-1-j) north to choose from
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OpenStudy (dan815):
which is
((n-1-i)+(n-1-j) )+choose (n-1-i)
OpenStudy (dan815):
((n-1-i)+(n-1-j) )choose (n-1-i)
OpenStudy (dan815):
for n=5
OpenStudy (dan815):
so u have 4 North an 4 east in n=5 so
8C4=70
ganeshie8 (ganeshie8):
\[\large \binom{2(n-1)}{n-1}\]
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ganeshie8 (ganeshie8):
would that work dan
OpenStudy (dan815):
yeah for B right
OpenStudy (dan815):
for d) i mean
ganeshie8 (ganeshie8):
in general.. for a square grid..
OpenStudy (dan815):
yep
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ganeshie8 (ganeshie8):
yes...
ganeshie8 (ganeshie8):
for part a, im still trying to understand how u got below :
((n-1-i)+(n-1-j) )choose (n-1-i)
OpenStudy (dan815):
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