Step-by-step explanation:
The unit circle is a circle in the form of
[tex] {x}^{2} + {y}^{2} = 1[/tex]
while x = cos t
y= sin t
, where t is an angle
So we plug in -1/7, for x to find y
[tex]( \frac{ - 1}{7} ) {}^{2} + {y}^{2} = 1[/tex]
[tex] {y}^{2} = \frac{49}{49} - \frac{1}{49} [/tex]
[tex]y = \frac{4 \sqrt{3} }{7} [/tex]
If the point is in the 2nd quadrant, your value of y is positive
If it in the third quadrant, the y value is negative
