Double Integral One Loop of the Rose

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SUMMARY

The discussion focuses on calculating the area of one loop of the polar rose defined by the equation r = cos(3θ) using double integrals. The incorrect setup of the integral was identified as ∫∫ (r*cos(3θ)) dr dθ, which does not yield the correct area. The correct approach involves using the formula for polar coordinates, specifically integrating the square of the radius function. The correct setup for the double integral should be ∫∫ (r^2) dr dθ, emphasizing the importance of proper variable representation in polar coordinates.

PREREQUISITES
  • Understanding of polar coordinates and their applications
  • Familiarity with double integrals in calculus
  • Knowledge of the area calculation for polar curves
  • Basic trigonometric identities and their use in integration
NEXT STEPS
  • Study the derivation of the area formula for polar curves
  • Practice solving double integrals with different polar equations
  • Learn about the properties of rose curves and their graphical representations
  • Explore advanced integration techniques in calculus, such as change of variables
USEFUL FOR

Students in calculus courses, mathematics educators, and anyone interested in mastering polar coordinates and double integrals for area calculations.

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Homework Statement



Use a double integral to find the area of one loop of the rose r = cos 3[itex]\theta[/itex]

Homework Equations





The Attempt at a Solution



This is a past test question. The only thing I got wrong was the set up while I got the rest of the mechanical steps right. I set up as

∫∫ (r*cos 3θ) dr dθ

which is not right. I thought it might either be

∫∫ (r*r) dr dθ

or

∫∫ (cos 3θ * cos 3θ) dr dθ
 
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Hint: r = cos theta, emphasis on equal
 

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