If m is the slope of a common tangent of the parabola y2 =16x and the circle x2 + y2 = 8, then m2 is equal to

Equation of a tangent to the parabola y2=16x is y=mx+4mIf this touches the circle of x2 + y2 = 8, then the distance of the centre (0, 0) of the circle from this tangent is equal to the radius 2 2 of the circle.    4m⇒    1+m2=22⇒    2=m2+m4⇒    m2+2m2−1=0⇒m2=1.