In case of parabola
y= x2-2x-3
Find:
a)Vertex:
b)Axis:
c)Focus:
d)Directrix:
e)Latus Rectum:
In case of parabola
y= x2-2x-3
Now,
y= x2-2x-3
x2-2x+1=y-3-1
(x-1)2=y-4......(i)
Let x-1= X and y+4=Y
Thus, the equation of parabola becomes, X2=Y......(ii)
Equating equation (ii) with the standard equation, X2=4aY
⇒4a = 1
⇒a = 1/4
Focus
X=0 and Y = 1/4
x-1= 0 and y+1=1/4
x=1 and y=(-3/4)
FOCUS= (1,-3/4)
Vertex
X=0 and Y = 0
x-1=0 and y+4=0
x=1 and y = -4
VERTEX=(1,-4)
Axis:
Since the given equation involves y , the axis of the parabola is the x-axis.
Latus Rectum
=4a
=4×(1/4)
=1
LATUS RECTUM = 1
Directrix
y+4+(1/4)=0
4y+17=0
DIRECTRIX=4y+17=0