Question

The point P is on the unit circle. If the y-coordinate of P is −3/5, and P is in quadrant IV, then

x = _________

Answer 1

`(4)/(5)`

Explanation:

Knowing that
`{-(3)/(5)}^(2) + {(4)/(5)}^(2) = 1, {-(3)/(5)}^(2) + {-(4)/(5)}^(2) = 1`,

so x can be positive or negative 4/5,

and we know that x coordinate of any point in quadrant IV is positive,

so x = 4/5.