JEE Main202126 Aug 2021Morning ShiftMathematicsStraight LinesActual
Let A B C be a triangle with A ( - 3 , 1 ) and ∠ A C B = θ , 0 < θ < π 2 . If the equation of the median through B is 2 x + y - 3 = 0 and the equation of angle bisector of C is 7 x - 4 y - 1 = 0 , then tan θ is equal to:
Options
- A3 4
- B4 3
- C2
- D1 2
Correct answer
B. 4 3
Step-by-step solution
Let, x - coordinate of the point C is α , So coordinate of the point C α , 7 α - 1 4 ∵ ( C  lies on  7 x - 4 y - 1 = 0 ) Hence, mid point of A C is m α - 3 2 , 7 α + 3 8 As, point m lies on the line 2 x + y - 3 = 0 , Substituting, we get α = 3 . So. C ( 3 , 5 ) Hence, slope of AC is 2 3 and slope of 7 x - 4 y - 1 = 0 is 7 4 ∴ tan θ 2 = 7 4 - 2 3 1 + 7 4 × 2 3 = 1 2 ⇒ tan θ = 2 · 1 2 1 - 1 4 = 4 3 ⇒ tan θ = 4 3