# HW 09-problems - waldon(scw2324 HW 09 he(53725 This...

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waldon (scw2324) – HW 09 – he – (53725) 1 This print-out should have 17 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. 001 10.0points From the contour map of f shown below decide whether f x , f y are positive, negative, or zero at P . 0 0 2 2 4 4 6 6 P x y 1. f x < 0 , f y > 0 2. f x > 0 , f y = 0 3. f x > 0 , f y < 0 4. f x < 0 , f y < 0 5. f x < 0 , f y = 0 6. f x > 0 , f y > 0 002 10.0points Determine f x - f y when f ( x,y ) = 4 x 2 + 2 xy - 3 y 2 + 3 x + y. 1. f x - f y = 6 x + 8 y + 4 2. f x - f y = 10 x - 4 y + 2 3. f x - f y = 6 x - 4 y + 2 4. f x - f y = 10 x - 4 y + 4 5. f x - f y = 10 x + 8 y + 4 6. f x - f y = 6 x + 8 y + 2 003 10.0points Determine whether the partial derivatives f x , f y of f are positive, negative or zero at the point P on the graph of f shown in P x z y 1. f x = 0 , f y < 0 2. f x > 0 , f y > 0 3. f x = 0 , f y > 0 4. f x = 0 , f y = 0 5. f x < 0 , f y > 0 6. f x < 0 , f y = 0 7. f x > 0 , f y = 0 8. f x < 0 , f y < 0 004 10.0points Determine f x when f ( x,y ) = ( y - x 2 )(2 y 2 + x ) .
waldon (scw2324) – HW 09 – he – (53725) 2 1. f x = 4 xy 2 + y - 3 x 2 2. f x = 4 xy 2 - y - 3 x 2 3. f x = y - 4 xy 2 - 3 x 2 4. f x = 2 y - 2 xy 2 + 3 x 2 5. f x = 2 xy 2 - 2 y + 3 x 2 6. f x = 2 y + 2 xy 2 + 3 x 2 005 10.0points Determine f x when f ( x, y ) = x sin( y - x ) + cos( y - x ) . 1. f x = - x cos( y - x ) 2. f x = x cos( y - x ) 3. f x = - cos( y - x ) - x sin( y - x ) 4. f x = x sin( y - x ) 5. f x = 2 sin( y - x ) - x cos( y - x ) 6. f x = - x sin( y - x ) 7. f x = x