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.

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