Saved Bookmarks
| 1. |
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 |
|
Answer» Option : (b) y = mx + 1 … . . (1) and y2 = 4x … … (2) Substituting (1) in (2) : (mx + 1)2 = 4x ⇒ m2x2 + (2m − 4)x + 1 = 0 … … . . (3) As line is tangent to the curve ⇒ line touches the curve at only one point ⇒ (2m − 4)2 − 4m2 = 0 ⇒ m = 1 |
|