Question

Question 1 Find the coordinates of the focus, axis of the parabola, the equation of directrix and the length of the latus rectum for y^2 = 12x

Class X1 - Maths -Conic Sections Page 246

Answer 1

concept :- if equation of parabola is in the form of y² = 4ax, then,
co-ordinate of focus ( a, 0)
axis of parabola = X - axis
equation of directrix , x = -a
Length of Latusrectum = 4a

Here, equation of parabola ,
y² = 12x
y² = 4( 3 )x , on comparing this with equation y² = 4ax . we get ,a = 3

hence, focus ( a , 0) = ( 3, 0)
axis of the parabola = X - axis
the equation of directrix , x = -3
Length of Latusrectum = 4a = 4 × 3 = 12