Question

Which of the following could be points on the unit circle?

Answer 1

equation of a unit circle with coordinates (x,y) is
\[x^2+y^2=1\]
now check for which pair above equation is satisfied

Answer 2

n

Answer 3

??

Answer 4

1,1?

Answer 5

ok try the second option
\[x=-2/3\\y=\sqrt{5}/3\]

Answer 6

square them and add them up and see if u get 1

Answer 7

any luck?

Answer 8

yes I got 1

Answer 9

\[x^2+y^2=[\frac{ -2 }{ 3 }]^2+[\frac{ \sqrt{5} }{ 3 }]^2=4/9+5/9=9/9=1\]

Answer 10

yes thats why this is on unit circle, try the other option you will not get 1.

Answer 11

ohhhhhhh so it's 1,1 and -2/3, 5/3?

Answer 12

no 1,1 is not correct because
\[1^2+1^2 \neq1~~so~this~is~eliminated\\ [\frac{ \sqrt{3} }{ 2 }]^2+(1/3)^2 \neq 1,this~is~eliminated\\ (0.8)^2+(-0.6)^2=1,so~this~is ~correct\\ (-2/3)^2+(\sqrt{5}/3)^2=1,so ~this~is~also~correct\]

Answer 13

so u have to take the numbers then square them add add them. if the addition produces 1 then they will be on unit circle,if not 1 then they will be not :)

Answer 14

ohhh ok I see