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candiwonderland
Group Title
i need to find dy/dt when x=8 and dx/dt=10
for xy=4
 one year ago
 one year ago
candiwonderland Group Title
i need to find dy/dt when x=8 and dx/dt=10 for xy=4
 one year ago
 one year ago

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satellite73 Group TitleBest ResponseYou've already chosen the best response.1
\[xy=4\] and i guess \(x=x(t)\) and \(y=y(t)\) i.e. they are both functions of \(t\) so via the product rule you get \[x'(t)y+y'(t)x=0\]
 one year ago

satellite73 Group TitleBest ResponseYou've already chosen the best response.1
it is easy to write \(x'\) than \(\frac{dx}{dt}\)
 one year ago

satellite73 Group TitleBest ResponseYou've already chosen the best response.1
now if \(x=8\) then since \(xy=4\) you know \(y=\frac{1}{2}\)
 one year ago

satellite73 Group TitleBest ResponseYou've already chosen the best response.1
and you are told \(x'=10\)
 one year ago

satellite73 Group TitleBest ResponseYou've already chosen the best response.1
solve \[x'(t)y+y'(t)x=0\] which is now \[10\times \frac{1}{2}+y'\times 8=0\] for \(y'\)
 one year ago

candiwonderland Group TitleBest ResponseYou've already chosen the best response.0
oh okay
 one year ago

candiwonderland Group TitleBest ResponseYou've already chosen the best response.0
thanks!
 one year ago
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