Let R\mathbb{R}R denote the set of all real numbers. Then the area of the region
{(x,y)∈R×R:x>0, y>1x, 5x−4y−1>0, 4x+4y−17<0}\left\{(x, y) \in \mathbb{R}\times\mathbb{R} : x > 0,\ y > \frac1x,\ 5x - 4y - 1 > 0,\ 4x + 4y - 17 < 0\right\}{(x,y)∈R×R:x>0, y>x1, 5x−4y−1>0, 4x+4y−17<0}
is
Official answer: B
Corners.
Area.∫12(5x−14−1x)dx+∫24(174−x−1x)dx.\int_1^2\left(\frac{5x-1}{4}-\frac1x\right)dx+\int_2^4\left(\frac{17}{4}-x-\frac1x\right)dx.∫12(45x−1−x1)dx+∫24(417−x−x1)dx.The first integral is 138−ln2\frac{13}{8}-\ln2813−ln2 and the second is 52−ln2\frac52-\ln225−ln2, soArea=138+52−2ln2=338−loge4.\text{Area}=\frac{13}{8}+\frac52-2\ln2=\frac{33}{8}-\log_e4.Area=813+25−2ln2=833−loge4.