CBSE Class 11-science Answered

(a) y² = 8x . It is a right handed parabola 4a = 8, a = 2.

Vertex (0,0)  Focus (2,0)  Axis : y = 0

Directix : x = -2 and length of latus rectum = 4 x 2 = 8.

(b) y² = -12x. It is a left handed parabola 4a = -12, a = -3

Vertex (0,0) Focus (-3,0) Axis y = 0.

Directix x = 3 and length of latus rectium = |4 x -3| = 12.

(c) x² = 4y. It is an upward parabola 4a = 4, a = 1.

Vertex (0,0) Focus (0,1) Axis x = 0

Directix y = -1, length of latus rectium = 4 x 1 = 4.

(d) x² = -16y. It is a downward parabola. 4a = -16, a = -4

Vertex (0,0) Focus (0,-4) Axis x = 0

Driectix y = 4, length of latus rectum = |4x -4| = 16.