1. Limited time only! Sign up for a free 30min personal 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!

Homework Help: Integral of (x^2)(sqrt(x^3 + 1))dx. Please check my work? Thank you!

  1. Jan 18, 2013 #1
    ∫x^2(√(x^3 + 1))

    u = x^3 + 1
    du = 3x^2dx
    (1/3)du = x^2dx


    = 2/3(u)^3/2 *(1/3)

    = 2/9(x^3 + 1)^3/2

    Is this the correct answer? Thank you.
  2. jcsd
  3. Jan 18, 2013 #2
    Yep, looks like it. You can always differentiate your answer if you're not sure.
  4. Jan 18, 2013 #3


    User Avatar
    Homework Helper

    Yes, but don't forget about the constant of integration.
  5. Jan 20, 2013 #4
    Thanks, you guys! :)

    That's true. I should differentiate when I'm not sure...
  6. Jan 20, 2013 #5

    Ray Vickson

    User Avatar
    Science Advisor
    Homework Helper

    You should differentiate even when you are sure! (Sometimes a person can be sure but still have the wrong answer.)

    In other words: always differentiate!
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook