NTA Abhyas JEE Main2020MathematicsHyperbolaPractice
Two straight lines having variable slopes m 1 and m 2 pass through the fixed points a , 0 and - a , 0 respectively. If m 1 m 2 = 2 , then the eccentricity of the locus of the point of intersection of the lines is
Options
- A2
- B3
- C2
- D3 2
Correct answer
B. 3
Step-by-step solution
Let, the lines are y = m 1 x - a and y = m 2 x + a which intersects at the point h , k . ⇒ k = m 1 h - a & k = m 2 h + a ⇒ k 2 = m 1 m 2 h 2 - a 2 ⇒ k 2 2 = h 2 - a 2 (given, m 1 m 2 = 2 ) ⇒ x 2 1 - y 2 2 = a 2 (Hyperbola) Eccentricity = 1 + 2 1 = 3