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Homework Help: One last problem

  1. Dec 11, 2003 #1
    I think Mr. Gishe went trigger happy when he was assigning homework today.

    [tex] y=\sqrt{a^2-x^2} [/tex] where -a<=x<=a is a semicircle with r=a
    show why [tex]\int_{-a}^{a} \sqrt{a^2-x^2}\,dx = \frac{1}{2} \pi a^2 [/tex]

    (I think that's how its written)
     
  2. jcsd
  3. Dec 11, 2003 #2
    What does the integral represent if the integrand is positive!!??? AREA!!!!!!!
    What's the area of a half circle?
     
  4. Dec 12, 2003 #3
    It is given in the que it is a semi-circle
    Do you know the area of circle
    if yes then u can find the area of semicircle

    or if u dont know n u want to calulate the integral

    substitute
    x=asinz
     
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