\(\int_{1}^{5}\displaystyle |x-2|\,dx =\)
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 5
The expression x − 2 changes sign at x = 2, so split the integral at 2:
\( \displaystyle \int_{1}^{5}|x-2|\,dx = \int_{1}^{2}(2-x)\,dx + \int_{2}^{5}(x-2)\,dx \)
First part:
\( \displaystyle \int_{1}^{2}(2-x)\,dx = \left[2x - \frac{x^2}{2}\right]_{1}^{2} \)
\( \displaystyle = 2 - \frac{3}{2} = \frac{1}{2} \)
Second part:
\( \displaystyle \int_{2}^{5}(x-2)\,dx = \left[\frac{(x-2)^2}{2}\right]_{2}^{5} \)
\( \displaystyle = \frac{9}{2} \)
So the integral is
\( \displaystyle \frac{1}{2} + \frac{9}{2} = 5 \)