Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Two variable calculus

  1. Feb 23, 2010 #1
    1. The problem statement, all variables and given/known data

    I have several problems:

    1. Calculate [tex]\int\[/tex] F . dr over C
    F = (y2,-x2) and C is the portion of the ellipse x2 + 4y2 = 4 which lies in the positive quadrant.

    2. Calculate [tex]\int[/tex] (3x2 + 3y2)1/2 ds where C is the part of the hyperbola x2 - y2 = 1 from (1,0) to (cosh2, sinh2).

    2. Relevant equations



    3. The attempt at a solution

    1. I have worked this out and got -20/3 but I'm unsure if it can be negative? I'm not very confident with working them out so am unsure about my answer. I can post more working if this is incorrect.

    2. I assume I need to use the parameters x=cosht, y=sinht and integrate from 0 to 2. However, I am confused as to what I multiply by after I have subbed in for x=cosht and y=sinht, before I integrate, if that makes sense.
     
    Last edited: Feb 23, 2010
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted