How to Solve Parabola Questions ( Tip-01)
→ 1st Tip
|
For Example → Find the focus and vertex
of x2=-24y???
|
|
Focus → First of all see in the
question where is the square whether it is in x or y.After seeing the
square,think (0,a)(where 0 is replaced because x2).If we have
equation like this y2=-24x then we think (a,0) because here y is squared.So
now we have to find a?.a is simple to find co-efficient of degree 1 is equal
to 4a(-24=4a).After solving this we get a=-6.So the focus of this equation is
(0,-6).
|
|
Vertex → Vertex of all these types
of equation(x2=4y,x2=-4y,y2=4x,y2=-4x)
is (0,0)
|
|
Directrix → Directrix is directly
related to a and sign of squared value.See above example where x is squared
so mean x=0(reference read focus portion) and a=-6(reference read focus
portion).So we get directrix y-6=0.If we have an equation like this y2=8x(here
a=2 and y=0) So x+8=0 is the directrix of this equation y2=8x
|
Sometimes questions
asked like this → Find the equation,if focus(0,-8) ,vertex(0,0) and options are
given.
|
Simply you have to find focus of
given options if any one of the option is matched with given focus,then that
will be the correct answer of given condition.
|
0 comments:
Post a Comment