Machine-translated by Google. Questions are authored in English.
Top

Discussion

If \(f(x) = 2\ln\left(\sqrt{e^{x}}\right)\), what is the area bounded by \(f(x)\) for the interval [0, 2] on the \(x\)-axis?

  • A.\(\dfrac{1}{2}\)
  • B.1
  • C.2
  • D.4

Answer: C

The area is 2.

Simplify the function first. Since \(\sqrt{e^{x}} = e^{x/2}\),

\[ \begin{aligned} f(x) &= 2\ln\left(e^{x/2}\right) \\ &= 2 \cdot \frac{x}{2} = x \end{aligned} \]

So the region is the triangle under the line \(y = x\) between \(x = 0\) and \(x = 2\):

\[ \int_{0}^{2} x\,dx = \frac{x^{2}}{2}\Big|_{0}^{2} = 2 \]

Dropping the factor 2 in front of the logarithm gives \(f(x) = x/2\) and an area of 1, and halving once more gives 1/2. 4 is \(x^{2}\) at \(x = 2\), the antiderivative without its division by 2.

No comment is present. Be the first to comment.
Loading…

Post your comment

Please log in or register to post a comment.