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SUROJ Group Title

Anybody know how to find the integral of following figure?

  • 2 years ago
  • 2 years ago

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  1. SUROJ Group Title
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    |dw:1352073105071:dw|

    • 2 years ago
  2. SUROJ Group Title
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    I mean area of the triangle using polar co-ordinates

    • 2 years ago
  3. TuringTest Group Title
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    using a double integral?

    • 2 years ago
  4. Algebraic! Group Title
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    rcostheta + rsintheta =1 r=1/(costheta +sintheta) \[\int\limits_{0}^{\frac{ \pi }{ 2 }} \frac{ r^2 }{2 } d \theta = \frac{ 1 }{ 2 }\int\limits_{0}^{\frac{ \pi }{ 2 }} \frac{ 1 }{(\cos \theta +\sin \theta )^2} d \theta \]

    • 2 years ago
  5. SUROJ Group Title
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    @TuringTest yes @Algebraic! how did u got that? can you explain some more?

    • 2 years ago
  6. Algebraic! Group Title
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    x=rcostheta y=rsintheta

    • 2 years ago
  7. Algebraic! Group Title
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    area = integral (r^2)/2 d theta

    • 2 years ago
  8. SUROJ Group Title
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    why is that?

    • 2 years ago
  9. sirm3d Group Title
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    the differential of of the area of a sector is given by \[dA=\frac{ 1 }{ 2 }r^2 d \theta \] so the area of the region is a definite integral \[A=\int\limits_{a}^{b}\frac{ 1 }{ 2 }r^2 d \theta \].

    • 2 years ago
  10. SUROJ Group Title
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    |dw:1352074998837:dw|

    • 2 years ago
  11. SUROJ Group Title
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    but we need to find area of triangle

    • 2 years ago
  12. SUROJ Group Title
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    @Algebraic! isn't that integral from 0 to pi/4

    • 2 years ago
  13. Algebraic! Group Title
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    pi/2

    • 2 years ago
  14. Algebraic! Group Title
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    are you in calc. 2?

    • 2 years ago
  15. SUROJ Group Title
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    Oh yea it's pi/2 thnks @Algebraic! ......but why dA is r^2/s d(theta)

    • 2 years ago
  16. Algebraic! Group Title
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    because the area of a circular sector is r^2 /2 times theta

    • 2 years ago
  17. SUROJ Group Title
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    Finally I got it thnks guys

    • 2 years ago
  18. sirm3d Group Title
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    |dw:1352076292545:dw| the small triangle is approximated by a sector of a circle.

    • 2 years ago
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