The line y = mx + 1 is a tangent to the curve y2 = 4x if the value of m is
It is given that the equation of the tangent to the given curve is
y = mx + 1
Now, substituting the value of y in y2 = 4x, we get
⇒ (mx + 1)2 = 4x
⇒ m2x2 + 1 + 2mx - 4x =0
⇒ m2x2 + x(2m - 4) + 1 = 0………………..(1)
Since, a tangent touches the curve at one point, the root of equation (1) must be equal.
Thus, we get
Discriminant = 0
(2m - 4)2 – 4(m2)(1) = 0
⇒ 4m2 + 16 - 16m - 4m2 =0
⇒ 16 – 16m = 0
⇒ m =1
Therefore, the required value of m is 1.