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Math Help - Help with area problem

  1. #1
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    Help with area problem

    Find the smaller of the two regions created by the curves x+7y=25 and x^2+y^2=25.
    Last edited by Chris L T521; December 12th 2010 at 03:59 PM. Reason: Restored original post.
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  2. #2
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    Quote Originally Posted by nickels View Post
    Find the smaller of the two regions created by the curves x+7y+25
    You'll need an equals sign for this if the question is to make sense, do you mean x+7y=25?

    Quote Originally Posted by nickels View Post
    and x^2+y^2=25.
    This is a circle centred at the origin, what is it's radius?
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  3. #3
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    oh yes, sorry
    i meant x+7y=25
    Last edited by Chris L T521; December 12th 2010 at 04:02 PM. Reason: Restored original post.
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  4. #4
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    I would say the area is equal to \displaystyle \int_a^b\sqrt{25-x^2}- \frac{25-x}{7}~dx where a and b are the intersections between the two functions.

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  5. #5
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    Yes, I follow, but when I try to solve the integral, I mess up
    Last edited by Chris L T521; December 12th 2010 at 04:03 PM. Reason: Restored original post.
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    Quote Originally Posted by nickels View Post
    Yes, I follow, but when I try to solve the integral, I mess up
    Separate into two parts

    \displaystyle \int_a^b\sqrt{25-x^2}~dx-\int_a^b \frac{25-x}{7}~dx

    For the first part use the substitution x=5\tan u the second one is a gimme!
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  7. #7
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    I'm still a little lost
    Last edited by Chris L T521; December 12th 2010 at 04:04 PM. Reason: Restored original post.
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  8. #8
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    Why did you delete your posts?
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