304,647 views
2 votes
2 votes
The point P=\left(-1/7, y) lies on the unit circle shown below. What is the value of y in its simplest form?

User Mwardm
by
2.4k points

1 Answer

15 votes
15 votes

Explanation:

The unit circle is a circle in the form of


{x}^(2) + {y}^(2) = 1

while x = cos t

y= sin t

, where t is an angle

So we plug in -1/7, for x to find y


( ( - 1)/(7) ) {}^(2) + {y}^(2) = 1


{y}^(2) = (49)/(49) - (1)/(49)


y = (4 √(3) )/(7)

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

User Muthu R
by
2.8k points
Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.