Home › AP EAPCET (Engineering) › Mathematics › Coordinate Geometry: Parabola › A parabola with vertex at origin has directrix x…
A parabola with vertex at origin has directrix x = -5. Its equation is:
Ay² = 5x
By² = -20x
Cy² = 10x
Dy² = 20x
Answer & Solution
Correct answer: D. y² = 20x
The directrix x = -a gives a = 5, and the curve opens right, so y² = 4(5)x = 20x.
Related questions
A point of y² = 4x is 5 units from the focus. What is its x-coordinate?A point moves so that its distance from (3, 0) equals its distance from x = -3. Find its lA lamp is placed at the focus of a parabolic reflector. The reflected beam isWhich device uses a parabolic reflector to send out a parallel beam?In the pin and string construction, the free edge of the set square slides along theHow far is the focus of y² = 24x from its directrix?What is the tangent at the vertex of y² = 4ax?The line y = x cuts a chord on y² = 4x. What is the chord length?