Integration by Substitution

AP Calculus AB· difficulty 4/5

01x1x2dx=\displaystyle \int_0^1 x \sqrt{1-x^2}\, dx =

  • A

    11

  • B

    12\frac{1}{2}

  • C

    13\frac{1}{3}

    check_circle
  • D

    23\frac{2}{3}

Explanation

Let u=1x2u=1-x^2, du=2xdxdu=-2x\,dx. Limits: x=0u=1x=0\to u=1, x=1u=0x=1\to u=0. Then 10u(du/2)=1201u1/2du=13\int_1^0 \sqrt{u}\cdot(-du/2) = \frac{1}{2}\int_0^1 u^{1/2}\,du = \frac{1}{3}.

Want 10 more like this — adaptive to your weak spots?

Related questions