## briana.img one year ago Graphing a circle. How to figure out the correct integers for the points?!

1. briana.img

I always thought the integers were the same

2. briana.img

I don't understand how they're positive I thought they would be negative

3. myininaya

what are you talking about exactly?

4. briana.img

@myininaya I thought the center coordinates for the second would be (-2,-1), but they're positive.. why is that?

5. myininaya

x-2=0 when x=2 and y-1=0 when y=1 so the center is (2,1)

6. myininaya

you can do that if confused to compare the equation to $(x-h)^2+(y-k)^2=r^2 \text{ where } (h,k) \text{ is center }$

7. myininaya

$(x-h)^2+(y-k)^2=r^2 \\ (x-2)^2+(y-1)^2=(\sqrt{18})^2$

8. briana.img

@myininaya so just set it equal to zero to get the coordinates?

9. myininaya

though you should see when comparing these that 2 is in the place of h and 1 is in the place of k

10. myininaya

yeah if it confused you to compare it to the equation above but you still need to make sure you have it in the form: $(x-h)^2+(y-k)^2=r^2$

11. briana.img

@myininaya so basically just it equal to zero

12. myininaya

oh and that was a 16 not a 18 i have bad eyes

13. myininaya

yes if you have it in the form: $(x-h)^2+(y-k)^2=r^2$ then yes

14. briana.img

@myininaya ok thx!!!