# Hey i thought that this is tricky but who knows

1. Nov 21, 2007

### therector24

[SOLVED] hey i thought that this is tricky but who knows

hey guys iam trying to solve this question
and this what i do have
https://www.physicsforums.com/attachment.php?attachmentid=11650&stc=1&d=1195680084

*i know that the radius is 1
*then the x = 0
*i think this question can be solved in two equations like those which are applied in knowing the center of mass ( in physics )
so guys can you help me in this question

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2. Nov 21, 2007

### Staff: Mentor

What can you show us about the equation for a circle, and how can you relate that to the equation shown for the parabola?

3. Nov 22, 2007

### therector24

hey why did you move that.,please replace it as its first condition, because first it is not a home work, second the circle equation is
((x^2)-x)+((y^2) - y)= R^2

4. Nov 22, 2007

### therector24

and why did i take a warning if you don't want to help just ignore, not to give me a warning

5. Nov 22, 2007

### quasar987

You get warnings from posting homework TYPE problems in the wrong section.

It's the mentor's job to give those warning it's not personal. It's like telling a police officier "hey, if you don't approve of *insert illegal activity of preference* just ignore, not to give me a warning."

6. Nov 23, 2007

### Staff: Mentor

Quasar explained why the thread was moved to Homework Help (thanks).

Now that you have the equation for the circle, since the circle touches the parabola at just two places as shown, how can you set up the simultaneous equations to give you the x,y coordinates where they touch? Remember, because of the symmetry of the situation, you only really have to solve for one of the two touching points in order to get them both....

7. Nov 24, 2007

### Gib Z

And the equation of that circle is actually $$x^2 + (y- y_1)^2 =1$$ where (0, y_1) is the center.

Last edited: Nov 24, 2007
8. Nov 29, 2007

### therector24

thanks for interesiting i solved it and the answer is (0 , 1.25). first i solved for the equation of a circle and then i got another equation which is ( the tangent * thenormal=-1)
whith a lot of my friend's help.
thanks again