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Antiderivative question?

Find the antiderivative by using substitution. Be sure to state clearly what you choose 𝑢 to

be. Show each of the steps and use 𝐶 as your constant of integration.

(integral) (2x)/(3x^2 - 4)^3

3 Answers

Relevance
  • 4 years ago

    ∫((2x)/(3x^2 - 4)^3)dx

    Let u = 3x^2 - 4

    Then du = 6xdx

    dx = du/6x

    ∫((2x)/(3x^2 - 4)^3)dx

    = ∫( 2x/u^3 * du/6x

    = 1/3∫ u^-3 du

    = 1/3 [ - 1/2 u^-2] + C

    = - 1/[6(3x^2 - 4)^2] + C

  • cidyah
    Lv 7
    4 years ago

    ∫ 2x / (3x^2-4)^3 dx

    Let u=3x^2-4

    du = 6x dx

    x dx = (1/6) du

    ∫ 2x / (3x^2-4)^3 dx = (2)(1/6) ∫ du/ u^3

    = (1/3) ∫ u^(-3) du

    = (1/3) u^(-3 +1)/(-3 +1)

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

    = -1 /(6u^2)

    replace u by (3x^2-4)

    = -1 /(6(3x^2-4)^2) + C

  • 4 years ago

    u = 3x^2 - 4 seems a logical choice since the numerator becomes part of du.

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