Question

The point `P(x, y)` is on the unit circle in quad IV, if `x= sqrt(11)/6`, how do you find `y`?

Answer 1

`y=-5/6`

Explanation:

Since `(x,y)` is on the unit circle
`color(white)("XXX")`x^2+y^2=1#

Substituting `sqrt(11)/6` for `x`
`color(white)("XXX")11/36+y^2=1`

`color(white)("XXX")rarr y^2=25/26`

`color(white)("XXX")rarr y = +- 5/6`

but we are told `(x,y)` is in Quadrant IV
therefore
`color(white)("XXX")y=-5/6`