JEE Main202331 Jan 2023Evening ShiftMathematicsParabolaActual
Let S be the set of all a ∈ N such that the area of the triangle formed by the tangent at the point P b , c , b , c ∈ N , on the parabola y 2 = 2 a x and the lines x = b , y = 0 is 16 unit 2 , then ∑ a ∈ S a is equal to _____ .
Correct answer
0
Step-by-step solution
Given, S be the set of all a ∈ N such that the area of the triangle formed by the tangent at the point P b , c ,   b ,   c ∈ N , on the parabola y 2 = 2 a x And the lines x = b , y = 0 is 16 unit 2 Now plotting the diagram we get, Tangent at P b , c will be a x - c y + a b = 0 and it meets x -axis at - b , 0 Now area of triangle P A B = 1 2 2 b c = 16 ⇒ b c = 16 So, b , c = 1 , 16 , 2 , 8 , 4 , 4 , 8 , 2 , 16 , 1 as both belongs to natural number, Now b , c lie on parabola hence satisfy