Question

if the point P(-4/5,y) is on the unit circle and P is in the 3rd quadrant, what is y equal to?

Answer 1

you know \((-\frac{4}{5})^2+y^2=1\) so you can solve for \(y\)

Answer 2

thanks :) i'll solve for it

Answer 3

or you can remember the 3 - 4 - 5 right triangle

Answer 4

i got y = (3/5), (-3/5)

Answer 5

is that right?

Answer 6

yes it is right, but there is only one answer, not two

Answer 7

or is y only equal to one of those values?

Answer 8

right, i have to check which one i forgot

Answer 9

because you are in quadrant 3 you the second coordinate is below the \(x\) axis and so it is negative

Answer 10

so y = (3/5)

Answer 11

oh sorry i didn't know it had to be negative

Answer 12

so in that case y would equal (-3/5)?

Answer 13

yes it is negative, but this should not be a mystery if you know what quadrant you are in

Answer 14

thanks, i forgot about the quadrant. thanks for the diagram

Answer 15

left and down, means both coordinates of that point are negative

Answer 16

thanks! i understand it much better now. can you please help me with another problem similar to this one? i'd really appreciate it, i'll post it now

Answer 17

yw (clear right?)

Answer 18

ok

Answer 19

yep, very clear :) thanks! i just posted the other one as well