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

Find the derivative: f(x) = 1/2x^2 + 3x^3

  1. Oct 9, 2006 #1
    I'm having problem with a problem =) can someone help.

    finding derivative:
    f(x) = 1/2x^2 + 3x^3

    i know there is a shortcut way to derivative, but i did the long way and got

    9x^2 - x

    is that correct? if not, can you tell me the step to solve it? thanks
  2. jcsd
  3. Oct 9, 2006 #2
    [tex] f(x) = \frac{1}{2x^{2}} + 3x^{3} [/tex].

    Use the power rule.

    [tex] \frac{d}{dx} (2x^{2})^{-1} = -1(2x^{2})^{-2}(4x) = -\frac{1}{x^{3}} [/tex].

    [tex] \frac{d}{dx} (3x^{3}) = 9x^{2} [/tex].

    [tex] \frac{dy}{dx} = -\frac{1}{x^{3}} + 9x^{2} [/tex]
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook