CBSE Class 12 Sample Paper for 2022 Boards (MCQ Based - for Term 1)
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CBSE Class 12 Sample Paper for 2022 Boards (MCQ Based - for Term 1)
Last updated at August 14, 2026 by Teachoo
This question is inspired from Misc 21 (MCQ) - Chapter 6 Class 12 - Application of Derivatives
Transcript
Question 42 For which value of m is the line y = mx + 1 a tangent to the curve y2 = 4x? (a) 1/2 (b) 1 (c) 2 (d) 3 Let (ā , š) be the point at which tangent is to be taken Since (š , š) lies on line š=šā+1 Since (š , š) lies on curve š^2=4ā ā=š^2/4 Putting (2) in (1) š=š(š^š/š)+1 4š=šš^2+4 šš^2ā4š+4=0 Since tangent touches the curve at only one point There is only one value of k So, this quadratic equation has only one root Thus, Discriminant of Quadratic equation = 0 š^šāššš=š (ā4)^2ā4 Ć š Ć 4=0 16ā16š=0 š=16/16 š=š So, the correct answer is (B)
