Directions
Read the following questions. Choose the right answer.
There is only ONE correct answer to each question.
The focus of the parabola represented by the equation (y − 3)² = −2x is:
- (0, 3.5)
- (0, 2.5)
- (1/2, 3)
- (−1/2, 3)
Show answer
Correct answer: D. (−1/2, 3)
Why
For (y−k)² = 4p(x−h) with vertex (h,k)=(0,3) and 4p=−2 (so p=−1/2), the focus is at (h+p, k) = (−1/2, 3).