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: Stuck on taking the integral of

  1. Aug 2, 2004 #1
    from 0 to 3, ( 1 + [ 1/2x^(1/2) - 1/2x^(-1/2) ]^2 )^(1/2) dx

    I started to foil the ^2 term and then tryed to use the u sub, but It doesn't seem to work out. this problem is killing me!!!
     
  2. jcsd
  3. Aug 2, 2004 #2

    HallsofIvy

    User Avatar
    Science Advisor

    Try that again! ((1/2)x1/2- (1/2)x-1/2)1/2=
    (1/4)x- 1/2+ (1/4)x-1.

    Now, when you add 1 to that you get (1/4)x+ 1/2+ (1/4)x-1. In other words, exactly the same thing except with +1/2 instead of -1/2!

    Now that = (what?)2.
     
  4. Aug 2, 2004 #3

    Zurtex

    User Avatar
    Science Advisor
    Homework Helper

    I think HallsofIvy is saying mess about with the algebra. I did and in a few steps got:

    [tex]\frac{1}{2} \int_0^3 x^{\frac{1}{2}} + x^{-\frac{1}{2}} dx[/tex]

    But I am not 100% confident on my skills so don't just copy that down.
     
  5. Aug 2, 2004 #4
    Another proof that you need to be good at algebra in order to be good at calculus.
     
  6. Aug 2, 2004 #5

    HallsofIvy

    User Avatar
    Science Advisor

    And you have to be good at calculus to be good at differential equations- and you have to be good at differential equations to be good at analysis, It just keeps going!!
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook