anonymous
  • anonymous
@Psymon
Mathematics
  • Stacey Warren - Expert brainly.com
Hey! We 've verified this expert answer for you, click below to unlock the details :)
SOLVED
At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.
katieb
  • katieb
I got my questions answered at brainly.com in under 10 minutes. Go to brainly.com now for free help!
anonymous
  • anonymous
1 Attachment
nincompoop
  • nincompoop
@mayafrancis are you going to post all of your math homework or at least try to figure things out yourself also?
anonymous
  • anonymous
its not homework i only post practices on here so ask questions first @nincompoop your dismissed i didn't ask for your input.

Looking for something else?

Not the answer you are looking for? Search for more explanations.

More answers

Psymon
  • Psymon
So first off the equation of a circle is \[(x-h)^{2}+(y-k)^{2}= r ^{2} \] The h is a movement left and right and the k is a movement up and down. So the h and the k tell us the coordinates of the center of a circle. So since the center of the circle is only at (0,0), we only have an x^2 + y^2 = r^2. As for the radius, r, this is the distance from themiddle of the circle to the edge of a circle. Now be careful, the distance from the center to the outer edge is r, NOT r^2. So always be mindful of that. You can tell what the radius is by just counting directly left, right, up or down from the middle. So for you, the distance from the center to the edge is just 1 unit. THis is r. And sense r = 1, r^2 is also just 1. Meaning the full equation ends up being \[x ^{2} +y ^{2}=1 \] Kinda make sense?
anonymous
  • anonymous
and also @nincompoop ! i dont ask for the answers i ask questions so i can understand better as you saw in my last post so dont make it seem like im not trying to learn.
nincompoop
  • nincompoop
okay babe, continue
anonymous
  • anonymous
@Psymon so that equation is for any question deal with circles?
anonymous
  • anonymous
dealing*
Psymon
  • Psymon
A better example to completely get the concept would be if the circle was not at the center and the radius was not 1. I think if we have a problem like that we can better show.
anonymous
  • anonymous
ooo ok make sense:)
Psymon
  • Psymon
Mhm. Like for an example I could give this:
Psymon
  • Psymon
|dw:1378097449129:dw| couldnt get the circle right, so had to hand draw xD So as mentioned, this is the formula for a circle: \[(x-h)^{2}+(y-k)^{2}= r ^{2}\] Now notice how I always put minus signs there. This means that the minus signs are supposed to be there and do not change. Because of this, if you ever see something liek (x+3)^2, this means the minus sign is gone. The only way for a minus sign to disappear is when you have something liek (x-(-3))^2 Because of this, if you ever see (x+4)^2 or some + sign inthose parenthesis, the number paired with it is actually negative. So h represents a shift left and right and k represents a shift up and down. SO from the picture, can you tell the coordinates of the center?
anonymous
  • anonymous
-2,2?
Psymon
  • Psymon
Other way around (2,-2) is the center. 2 units positive on the x-axis and 2 units negative onthe y-axis. Do you understand why the center is (2,-2)?
anonymous
  • anonymous
not really
nincompoop
  • nincompoop
you have to read the coordinate as is, which is (x,y) in the cartesian
nincompoop
  • nincompoop
|dw:1378097980233:dw|
nincompoop
  • nincompoop
|dw:1378098054916:dw|
anonymous
  • anonymous
oooo ok thanks.
nincompoop
  • nincompoop
thank psymon. he did the job
anonymous
  • anonymous
i did
nincompoop
  • nincompoop
I can put up a more comprehensive example if you want with detailed steps
Psymon
  • Psymon
Mhm. So now you have to plug those coordinates into the equation of a circle. Remember. (x - ___)^2 means the number is positive and (x + ___)^2 means the number is negative. SO we have a positive 2 x-value, meaning we have (x-2)^2. We have a negative y-value meaning we have (y+2)^2. So this gives us everything but the actual radius. Now since the radius is the distance from the center of the circle to any point on the edge, we can just count and visually see the radius is 2. Now again, this radius of 2 is r, not the r^2 required in the equation. So squaring our radius, we simply get 4. So the full equation of the circle is: \[(x-2)^{2}+(y+2)^{2}=4 \] If that makes any sense, lol.
nincompoop
  • nincompoop
The point (3, 4) lies on a circle whose center is at (-1, 2). Write the standard form of equation of this circle. |dw:1378098432525:dw|
nincompoop
  • nincompoop
|dw:1378098804877:dw|

Looking for something else?

Not the answer you are looking for? Search for more explanations.