Recent content by Hammie

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    Combinatorics - can't really identify the problem

    If I read the problem correctly, you end up giving all 24 cans to the students. Why not just count the ways this can be done? first you must hand two cans to each, as they must receive at least two cans. Then figure out how to distribute the remaining 18 among three students. label them 1, 2...
  2. H

    Instantaneous rates of change. Exponential growth and Decay

    In your first equation, where did you get the 48 from? Maybe it should be 52. Then at t=4weeks, you would have t=4/52 years. I think your answer is in terms of years, not weeks. Same for the second equation. You converted 18 months into 1.5 years. The solution you have is in terms of grams...
  3. H

    Given a discontinuos function, show that it is not concave

    at this level of mathematics.. if you can even understand the question, you should get an "A".. :)
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    Given a discontinuos function, show that it is not concave

    so what you are trying to show is that if the function is not continuous, that it is convex?
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    Typical calculus qn. try to solve without calculus

    so, by the constraint you have two numbers which add up to twenty. Call one x, and the other 20-x. square both, and add. what do you know about a quadratic that gives a maximum or minimum?
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    Given a discontinuos function, show that it is not concave

    what kind of class is this problem from? A little context might help know where to go. I might be able to help you with showing a midpoint convex function is convex if it is continuous..
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    What am I overlooking? Vectors simple problem

    My first observation: You do not know the speed of the plane. If you assign a vector <1,1> here, you may be saying that the plane is traveling at sqrt(2) ground speed. adding the big vector, you can see you are actually reversing the direction of the plane. I think a good assumption would be...
  8. H

    There is something wrong with this vector problem

    The wind from the west is moving east. I think that is the problem here.. the east wind is contributing to the horizontal component you posted. In other words, I think you may want to try adding instead of subtracting.
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    There is something wrong with this vector problem

    what vectors did you add? You have to separate the original vector into horizontal and vertical components. then add the individual horizontal and vertical components. the wind form the west, does not add or subtract from the vertical component. A reasonable answer as to ground speed would...
  10. H

    Two-variable limit problem

    It is a lot easier to show the limit does not exist. All you have to do is find one path towards (0,0) that produces a limit that is not zero. Maybe you could try a quadratic, or a cubic..
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    How is equation transformed by matrix

    Or you could use the hint. You have an equation of a line. Find the coordinates for two points. If you have two coordinates, can you find the vector? Matrices transform vectors to vectors by multiplication.
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    How is equation transformed by matrix

    One way to try this problem would be to parametrize your line, and express it as a vector, then see how your matrix will map it.
  13. H

    Quick question on integral calculation

    Did you calculate the derivative?
  14. H

    Looking for old documents

    Anybody have anything?
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