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Zorluk: KolayDefinite Integrals and Area Under Curves

What is the value of the definite integral 04xdx\int_{0}^{4} \sqrt{x} \, dx?

  1. 163\frac{16}{3}Cevap
  2. B
    88
  3. C
    1212
  4. D
    83\frac{8}{3}

Cevap

163\frac{16}{3}
Applying the power rule to x1/2x^{1/2} gives 23x3/2\frac{2}{3}x^{3/2}. Substituting the upper limit x=4x = 4 yields 23(4)3/2=23(8)=163\frac{2}{3}(4)^{3/2} = \frac{2}{3}(8) = \frac{16}{3}, and substituting the lower limit x=0x = 0 yields 0. Subtracting the lower limit result from the upper limit result gives 163\frac{16}{3}.

Adım Adım Çözüm

1
Express the integrand with a fractional exponent
x=x1/2\sqrt{x} = x^{1/2}
Rewriting the square root as a fractional exponent allows the application of the power rule of integration.
2
Find the antiderivative using the power rule of integration
x1/2dx=x1/2+11/2+1=x3/23/2=23x3/2\int x^{1/2} \, dx = \frac{x^{1/2 + 1}}{1/2 + 1} = \frac{x^{3/2}}{3/2} = \frac{2}{3}x^{3/2}
The power rule states that xndx=xn+1n+1\int x^n \, dx = \frac{x^{n+1}}{n+1} for n1n \neq -1.
3
Evaluate the antiderivative at the limits 4 and 0
[23x3/2]04=23(4)3/223(0)3/2=23(8)0=163\left[ \frac{2}{3}x^{3/2} \right]_{0}^{4} = \frac{2}{3}(4)^{3/2} - \frac{2}{3}(0)^{3/2} = \frac{2}{3}(8) - 0 = \frac{16}{3}
By the Fundamental Theorem of Calculus, evaluate F(b)F(a)F(b) - F(a).

Anahtar Kavram

Definite Integration using the Power Rule
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