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anonymous
 5 years ago
solve max and min
f(x,y) = 2xy subject to x^2 +y^2 = 18
anonymous
 5 years ago
solve max and min f(x,y) = 2xy subject to x^2 +y^2 = 18

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anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0Use polar coordinates. so x=rcos(theta) y=rsin(theta). So you get r=3root3. now f(x,y)=f(rcostheta,rsintheta)=2r^2sinthetacostheta. We know that r=3root3. So plug in r in f(x,y), so then f(rcostheta,rsintheta)=2(9)(3)(sin)(cos). Now take a partial derivative with respect to thetha and set it equal to 0. and solve for theta

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0oh I thought we use Lagrange multipliers\[\lambda\]

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0Oh lagrange multipliers also work!
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