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← JEE Advanced 2025 · Paper 2
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JEE Advanced 2025 · Paper 2, Mathematics question 2

Let R\mathbb{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\}

is

Choose one option
Answer and worked solution

Official answer: B

Corners.

  • The lines y=5x−14y=\frac{5x-1}{4} and y=174−xy=\frac{17}{4}-x meet at (2,94)(2,\frac94).
  • y=1xy=\frac1x meets the first line at x=1x=1.
  • y=1xy=\frac1x meets the second line at x=4x=4.

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.
The first integral is 138−ln⁡2\frac{13}{8}-\ln2 and the second is 52−ln⁡2\frac52-\ln2, so
Area=138+52−2ln⁡2=338−log⁡e4.\text{Area}=\frac{13}{8}+\frac52-2\ln2=\frac{33}{8}-\log_e4.