AP EAMCET Engineering 2018 Apr 24 Shift 1 Paper

The parabola is represented in the figure below
The coordinate of A is (x1,8) and the coordinate of B is (x1,−8)
Put these coordinates in the equation of parabola.
x1=8 .
tan‌α=

8

8

=1
α=

π

4

The angle subtended at the vertex =2α=

π

2