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

Ques 9 (MCQ) - Class 12 Sample Paper - The point at which normal to - CBSE Class 12 Sample Paper for 2022 Boards (MCQ Based - for Term 1)

part 2 - 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 - Class 12
part 3 - 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 - Class 12 part 4 - 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 - Class 12

Remove Ads
Teachoo Ā· Class 12 Explore Class 12

Transcript

Question 9 The point at which the normal to the curve y = š‘„ + 1/š‘„, x > 0 is perpendicular to the line 3x – 4y – 7 = 0 is: (a) (2, 5/2) (b) (±2"," 5/2) (c) (āˆ’1/2 " ," 5/2) (d) (1/2 " ," 5/2) Finding Slope of Normal y = x + 1/š‘„ Differentiating both sides š‘‘š‘¦/š‘‘š‘„ = 1 āˆ’ 1/š‘„^2 Now, Slope of Normal = (āˆ’šŸ)/(šŸ āˆ’ šŸ/š’™^šŸ ) Given that Normal is perpendicular to 3x āˆ’ 4y = 7 So, Slope of Normal Ɨ Slope of Line = āˆ’1 (āˆ’1)/(1 āˆ’ 1/š‘„^2 ) Ɨ 3/4 = āˆ’1 3/4 = 1 āˆ’ 1/š‘„^2 1 āˆ’ 1/š‘„^2 = 3/4 1 āˆ’ 3/4 = 1/š‘„^2 1/4 = 1/š‘„^2 x2 = 4 x = ± 2 Since x > 0 ∓ x = 2 Finding y when x = 2 y = x + 1/š‘„ y = 2 + 1/2 y = šŸ“/šŸ Thus, Point at which normal is perpendicular to line = (x, y) = (2, šŸ“/šŸ) So, the correct answer is (a)

Davneet Singh's photo - Co-founder, Teachoo

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.

Many students prefer Teachoo Black for a smooth, ad-free learning experience.