Highly selective Backlog Qs for JEE MainMathematicsParabola
The length of the chord of the parabola y²=4 a x(a>0) which passes through the vertex and makes an acute angle with the axis of the parabola is
Options
- A4 a cosec
- B4 a cosec
- C-4 a cosec
- D4 a cosec ²
Correct answer
B. 4 a cosec
Step-by-step solution
Hint: Equation of OP:- y=x Solving with y²=4 a x , we get : x² ² =4 a x x=4 a ² Substituting, y=4 a P (4 a ² , 4 a ) So, OP = 16 a ² ⁴ +16 a ² ² =4 a cosec ( . as 0^ < < 90^ , so . >0, cosec >0 )