Question

If the focus is (1, –1) and the directrix is the line x + 2y – 9 = 0, the vertex of the parabola is

• A. (1, 2)
• B. (2, 1)
• C. (1, –2)
• D. (2, –1)

Answer 1

The correct option is B (2, 1)

S(1, –1). Foot of the $\perp lr$ from S(1, –1) on x + 2y – 9 = 0 is Z (3, 3)
Mid point of SZ is the vertex $[\frac{1+3}{2},\frac{-1+3}{2}]=(2,1)$