JEE Main202227 Jul 2022Evening ShiftMathematicsParabolaActual
If the length of the latus rectum of a parabola, whose focus is a , a and the tangent at its vertex is x + y = a , is 16 , then a is equal to
Options
- A2 2
- B2 3
- C4 2
- D4
Correct answer
C. 4 2
Step-by-step solution
Given the equation of tangent at vertex is x + y = a and the focus is a , a Now the perpendicular distance from focus to tangent is a + a - a 2 = a 2 Also given length of latus rectum = 16 i.e. a 2 = 16 4 = 4 ⇒ a = 4 2