JEE Main 2021 · MathsMultiple choiceSingle correctMediumMulti-step

JEE Main 26 August 2021, Shift 2, Maths Q69

Question 69 of 90 in this shift, Maths question 9 of 30, Section A.

A 10 inches long pencil AB with mid point C and a small eraser P are placed on the horizontal top of a table such that

\mathrm{PC}=\sqrt{5}

inches and

\angle\mathrm{PCB}=\tan^{-1}(2)

. The acute angle through which the pencil must be rotated about C so that the perpendicular distance between eraser and pencil becomes exactly 1 inch is :

The figure, in words

A horizontal pencil drawn as a long cylinder with ends A (left) and B (right), midpoint C marked, each half labelled 5 in. A line segment from C to a point P above the pencil, labelled

\sqrt{5}

in.

(1) $\tan^{-1}\left(\frac{4}{3}\right)$
(2) $\tan^{-1}\left(\frac{3}{4}\right)$ Official answer
(3) $\tan^{-1}(1)$
(4) $\tan^{-1}\left(\frac{1}{2}\right)$

Official answer

Option 2

NTA final key.

Chapter: Trigonometric Functions
Topic: Straight Line Distance
Idea tested: Perpendicular distance from point

JEE Main 26 August 2021, Shift 2, Maths Q69

Same idea in other shifts