1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Area of Polar Coordinates

  1. Oct 19, 2007 #1
    [SOLVED] Area of Polar Coordinates

    1. The problem statement, all variables and given/known data
    Find the area of the region bounded by r=6-4sin[tex]\Theta[/tex]


    2. Relevant equations
    A=(1/2)[tex]\int[/tex] r[tex]^{2}[/tex] d[tex]\Theta[/tex]


    3. The attempt at a solution
    I'm not sure what the bounds are but I thought they were 0 to 2pi. Am I wrong if so how then do you go about finding the bounds?
    A=(1/2)[tex]\int[/tex] [36-48sin[tex]\Theta[/tex]+16sin^2[tex]\Theta[/tex] d[tex]\Theta[/tex]
    A=(1/2)[36[tex]\Theta[/tex]-48cos[tex]\Theta[/tex]+8[tex]\Theta[/tex]-4sin2[tex]\Theta[/tex]]

    and i got the answer to be 63.5 where did i go wrong?
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Oct 19, 2007 #2

    arildno

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    Dearly Missed

    How do get [tex]44\pi=63.5[/tex]???
     
  4. Oct 19, 2007 #3
    I'm not sure what i did. I think i typed in the wrong thing in my calculator or something. but i just plugged 2pi and 0 in for theta, but i still got the wrong answer. What am i suppose to do.
     
  5. Oct 20, 2007 #4

    arildno

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    Dearly Missed

    Do it by hand, then, and see if you get 44*pi.

    One possible reason why your calc gave you something else than that might be that your calculator is measuring angles in degrees instead of radians.
     
  6. Oct 20, 2007 #5
    yeah you're right i forgot to change back to radians, i feel so stupid now. well thanks, maybe i should just do by hand and not put so much trust in the calculator.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Area of Polar Coordinates
Loading...