giive me the shortest method..

find coordinates of point on parabola y2=8x which is at min distance from circle x2+(y+6)2=1

is differentiation the only method ??
can we get answer by observation only ??

4 Answers

66
kaymant ·

Draw a graph (which makes this problem almost trivial). The point is that the minimum distance will occur along the line which is normal to the circle as well as the parabola.

1
sam X ·

yes....and the common normal must pass through the centre of the circle !

3
iitimcomin ·

y=-tx+4t+2t^3 must pass thru 0,-6

-6 = +4t + 2t^3 t = -1

therefore pt ==> 2,-4

3
iitimcomin ·

arshad 2 steps dude ....

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