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f(x,y)=ln(1-x^2-y^2)-x-y
a) What is the functions def.amount meaning what allowed x-values are there?
b) Find the functions stationary dots (meaning highest, lowest) and classify them.
I have tried following the examples in the book but no advance since maths really isn't my strongest side. Since I´m in university I have noone to turn to atm and this assignment is due to get handed in tomorrow. I have tried all weekend without succes, any help or pointers would be appreciated. Thanks in advance /Brian
Last edited by gossen (2006-09-17 01:34:20)
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*Bump* , anyone?
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To figure out what x values are allowed, first you must figure out what x values aren't allowed. Can we take the ln of anything less than 0? What value of x would make the stuff inside the ln always less than 0, no matter what y is?
As for finding max and mins, do you know the chain rule? If you do, find the derivative of f(x, y) with repect to both x and y, set that to 0 to find the critial points, then find which of these points is the lowest and which is the highest.
"In the real world, this would be a problem. But in mathematics, we can just define a place where this problem doesn't exist. So we'll go ahead and do that now..."
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Wow thanks Ricky, I think it worked :DD
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No problem. If you would share your answer with us, we could check it over if you like.
"In the real world, this would be a problem. But in mathematics, we can just define a place where this problem doesn't exist. So we'll go ahead and do that now..."
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