When the axis of symmetry is along the x-axis the parabola opens to the
o right if the coefficient of x is positive , o left if the coefficient of x is negative .
When the axis of symmetry is along the y-axis the parabola opens
o upwards if the coefficient of y is positive . o downwards if the coefficient of y is negative .
Latus Rectum of Parabola
Latus rectum of a parabola is a line segment perpendicular to the axis of the parabola , through the focus and whose end points lie on the parabola .
Length of latus rectum of the parabola y 2 = 4ax , is 4a
Numerical : Find the coordinates of the focus , axis , the equation of the directrix and latus rectum of the parabola y 2 = 8x .
Solution : the parabola equation involves y 2 , so the axis of symmetry is along the x-axis .
The coefficient of x is positive so the parabola opens to the right . Comparing with the given equation