Question

If the point P(-3/5,y) lies on the unit circle and P is in the second quadrant, what does y equal?

Answer 1

Use the equation for the unit circle to solve for y.

Explanation:

The unit circle has a radius equal to 1 and is centered at the point (0,0). Therefore, the equation for the unit circle is:

`x ^ 2+ y ^ 2 = 1`

Now use the coordinates of point P and substitute into the above equation:

`(-3/5) ^ 2+ y ^ 2 = 1`

Next, solve for y:

`y ^ 2 = 1 - (9/25) = 16/25`

`y = +- 4/5`

Finally, we know from the problem that P lies in the second quadrant. In the second quadrant, X is negative and Y is positive. Therefore, the final answer is:

`y = + 4/5`

Hope that helps!