If $y=mx+1$ is a tangent to the parabola $y^2=4x$,then $m=$

If the line $y = -x + k$ is normal to the curve $y^2 = 16x$,then $k$ is

What is the condition for the points $(a, 0)$,$(at_1^2, 2at_1)$,and $(at_2^2, 2at_2)$ to be collinear?

If the midpoint of a chord is $(-1, 1)$,find the equation of the chord of the parabola $y^2 = 6x$.

The length intercepted by the curve $y^2 = 4x$ on the line satisfying $dy/dx = 1$ and passing through the point $(0, 1)$ is given by

Three normals drawn from any point to the parabola $y^2 = 4ax$ cut the line $x = 2a$ in points whose ordinates are in arithmetical progression. Then the tangents of the angles which the normals make with the axis of the parabola are in: