Question

Coordination Geometry question #2 - circle

Answer 1

I and II.

Answer 2

if need explain tell me

Answer 3

Sorry, but if the answer is correct, then yours would be wrong...

Answer 4

ups, you right i did for x axis, my bad

Answer 5

answer would be II adn III

Answer 6

If I give a random answer can I still get a medal :p

Answer 7

Seems you've got what you want...

Answer 8

need explain, if no say so. TuringTest is hunting me...:) for answers with no explain

Answer 9

@myko the way you get the answer is my concern!!!

Answer 10

lolols I wasn't serious hahaha that is too much for meh ...your problem is

Answer 11

@myko lol don't worry, I would do the hunting job myself first :)

Answer 12

Perhaps just explain one of the cases. I would try for the rest. I don't want to be fed with the solution only :)

Answer 13

Substitute x=0 in each equation. If you get a real value for y, then the circle intersects the y-axis, otherwise not. (RRemember that k<h)

Answer 14

ok, here it goes...
the equation of the circle in the for it's given is telling you the center of it and it's radius. ( x-h)2 +(y-k)2 = r2
Center would be (h,k) and radius sqrt(r)
So you see, the circle is moved to point (h,k) with radius sqrt(r)
so if radius is less than k it won't touch the y axis

Answer 15

where i wrote sqrt(r) should say sqrt(r2)

Answer 16

@Mani_Jha Thanks for the hints, I got it by checking delta :)
@myko don't really understand your method :S

Answer 17

My method is the most simple one you can imagin @Callisto

Answer 18

@myko, I think you're checking whether the circle touches(that means, whether y-axis is a tangent) the y-axis. But the question just asks for intersection, and for that there's no necessity of a tangent.

Answer 19

@myko How did you determine that I is not the answer?

Answer 20

i just check if the distance that the center of the circle is moved from y axis is more, less or equal to it's radius @Mani_Jha

Answer 21

if it's tangent is also valid @Mani_Jha

Answer 22

@myko what about my question.... /____\ ???

Answer 23

I is not the answer becouse it says that k<h and the (x-h) term says that this distance is more than k. So it won't reach the y axis

Answer 24

wrong quadrant, sry. But the idea is still the same