Question

Given this unit circle what is the value of x? HELP PLEASE

Answer 1

x = -
`(3)/(5)`

Explanation:

consider the right triangle formed by the x- axis, the y- coordinate of the given point and the radius of the circle 1 , to the point from the centre.

using Pythagoras' identity

x² + (
`(4)/(5)` )² = 1²

x² +
`(16)/(25)` = 1 ( subtract
`(16)/(25)` from both sides )

x² = 1 -
`(16)/(25)` =
`(9)/(25)` ( take square root of both sides )

x² = ±
`\sqrt{(9)/(25) }` = ±
`(√(9) )/(√(25) )` = ±
`(3)/(5)`

since the given point is in the second quadrant , then

x = -
`(3)/(5)`