Question 9 - CBSE Class 12 Sample Paper for 2022 Boards (MCQ Based - for Term 1) - Solutions of Sample Papers and Past Year Papers - for Class 12 Boards
Last updated at August 14, 2026 by Teachoo
The point at which the normal to the curve y = š„ + 1/x, x > 0 is perpendicular to the line 3x – 4y – 7 = 0 is:
(a) (2, 5/2) (b) (±2, 5/2)
(c) (-1/2, 5/2) (d) (1/2 , 5/2)
This question is
inspired from
Question 22
-
CBSE Class 12 Sample Paper for 2021 Boards
Question 9 The point at which the normal to the curve y = š„ + 1/š„, x > 0 is perpendicular to the line 3x ā 4y ā 7 = 0 is: (a) (2, 5/2) (b) (±2"," 5/2) (c) (ā1/2 " ," 5/2) (d) (1/2 " ," 5/2)
Finding Slope of Normal
y = x + 1/š„
Differentiating both sides
šš¦/šš„ = 1 ā 1/š„^2
Now,
Slope of Normal = (āš)/(š ā š/š^š )
Given that
Normal is perpendicular to 3x ā 4y = 7
So,
Slope of Normal Ć Slope of Line = ā1
(ā1)/(1 ā 1/š„^2 ) Ć 3/4 = ā1
3/4 = 1 ā 1/š„^2
1 ā 1/š„^2 = 3/4
1 ā 3/4 = 1/š„^2
1/4 = 1/š„^2
x2 = 4
x = ± 2
Since x > 0
ā“ x = 2
Finding y when x = 2
y = x + 1/š„
y = 2 + 1/2
y = š/š
Thus,
Point at which normal is perpendicular to line = (x, y)
= (2, š/š)
So, the correct answer is (a)
Made by
Davneet Singh
Davneet Singh is an IIT Kanpur graduate and has been teaching for 16+ years. At Teachoo, he breaks down Maths, Science and Computer Science into simple steps so students understand concepts deeply and score with confidence.
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