Q240 / 270 · NDA 2023 (Phase 2) · Mathematics
What is the sum of the intercepts of the line whose perpendicular distance from origin is 4 units and the angle which the normal makes with positive DIRECTIONS of $x$-axis is $15^{\circ}$ ?
- A8
- B$4 \sqrt{6}$
- Correct answerC$8 \sqrt{6}$
- D16
Solution
Since, equation of normal is
$\mathrm{x} \cos \alpha+\mathrm{y} \sin \alpha=\mathrm{P}$
$\Rightarrow \mathrm{x} \cos 15^{\circ}+\mathrm{y} \sin 15^{\circ}=4$...(i)
If $y=0 \Rightarrow x=\frac{4}{\cos 15^{\circ}}=\mathrm{a}=$ intercept on X -axis
If $x=0 \Rightarrow y=\frac{4}{\sin 15^{\circ}}=b=$ intercept on Y-axis
Now, $a+b=\frac{4}{\cos 15^{\circ}}+\frac{4}{\sin 15^{\circ}}=8 \sqrt{6}$
Hence, the correct answer is option: 'C'.