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: Double integral help

  1. Mar 16, 2006 #1
    [tex]\int _0 ^{\pi/3} \int _0 ^{\pi/4} x cos(x+y) dy dx[/tex]
    [tex]\int _0 ^{\pi/3} xsin(x+\frac{\pi}{4}) dx [/tex]
    using u-sub, u=x, dv=sin(x+pi/4)

    [tex]-xcos\left(x+\frac{\pi}{4}\right)+ sin\left(x+\frac{\pi}{4}\right)-sin\left(\frac{\pi}{4}\left) |_0^{\pi/3} [/tex]

    [tex]-\frac{\pi}{3}cos\left(\frac{\pi}{3}+\frac{\pi}{4}\right)+ sin\left(\frac{\pi}{3}+\frac{\pi}{4}\right)-sin\left(\frac{\pi}{4}\right) [/tex]

    i dont know where I made the mistake
     
    Last edited: Mar 16, 2006
  2. jcsd
  3. Mar 16, 2006 #2

    Galileo

    User Avatar
    Science Advisor
    Homework Helper

    Don't forgot the lower limit in the first integration: [itex]\sin(x+\pi/4)-\sin(x)[/itex]
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook