Question

The equation of a circle center at the origin and radius 1is ?

Answer 1

x^2 +y^2 =1

Answer 2

explain why please
ill give you a medal if you explained it well

Answer 3

there isnt anyway of explaining it really lol

Answer 4

the general form a circle with centre (a,b) and radius r is \[(x-a)^2 +(y-b)^2 =r^2\]

Answer 5

here centre is (0,0)

yeh.. theres not alot of explaining, you have to remember the formula , thats all you can do

Answer 6

i can explain

Answer 7

ok lets go back to geometry definition

Answer 8

you there?

Answer 9

ok

Answer 10

ohh its phytagorus , yeh

Answer 11

yes

Answer 12

the locus definition

Answer 13

a circle is a set of points such that, the distance from the center is fixed

Answer 14

right

Answer 15

a circle is a locus of points whose distance from a point is constant, that distance is the radius

Answer 16

thats the ancient greek definition, going back when

Answer 17

now fast forward to cartesian world, we have x y graph

Answer 18

your center lets say for convenience is origin (0,0)

Answer 19

ok so far?

Answer 20

your doing it the really long way, not very good explaination lol

Answer 21

ill do it

Answer 22

ok
but please explain easier to understand

Answer 23

he wants a thorough explanation

Answer 24

we want d( (x,y) (0,0) = r

Answer 25

the distance between (0,0) and the points (x,y) to be the constant radius

Answer 26

ok so far? , and we know the distance between any two points using the distance formula

Answer 27

elec, this is not easy to understand? i can show a graph , but this interface sucks balls

Answer 28

you can just go straight to the general case centre (a,b)
\[\sqrt{(x-a)^2 +(y-b)^2} = r \]

Answer 29

please explain it like you are explaining it to a kid

Answer 30

then square both sides

Answer 31

d ( (x1,y1) (x2,y2) ) = sqrt ( (x1-x2)^2 + (y1-y2)^2)

Answer 32

right that works

Answer 33

WAIT!

Answer 34

so the distance between any arbitrary center (h,k) and the points (x,y) is some distance r.
d ( h,k)(x,y) = r

Answer 35

, so sqrt ( (x-h)^2 + ( y - k)^2) = r

Answer 36

this is a deductive proof my friend :)

Answer 37

my teacher gave me a really easy solution for this and i just forgot it
and then i wrote the equation x^2+y^2=r^2
and i forgot what it means

Answer 38

on my ntbk

Answer 39

if you draw a line from your center to a point on the circle, and then draw a triangle

Answer 40

you get pythagorean triangle

Answer 41

please don't give me a complicated solution

Answer 42

ok youre annoying, bye

Answer 43

then?

Answer 44

youre doing it right

Answer 45

then what?

Answer 46

lols

Answer 47

then the world ends tomorrow

Answer 48

brb, i will use a whiteboard , this is no good

Answer 49

ahhhh ok

Answer 50

a more interesting question has peaked my curiosity, brb

Answer 51

ill just give you both a medal^_^

Answer 52

for answering and explaining^_^

Answer 53

complex numbers: find a, b such that (-bi)^2 = a^2 ?

Answer 54

this question is ambiguous, ok one sec

Answer 55

here click on this http://www.twiddla.com/542364

Answer 56

what is this?

Answer 57

circle centre (2,3), radius 2

Answer 58

its pretty basic

Answer 59

it is alright know^_^