Conic Sections Question 133

Question: The equation of common tangents to the parabola $ y^{2}=8x $ and hyperbola $ 3x^{2}-y^{2}=3 $ , is

Options:

A) $ 2x\pm y+1=0 $

B) $ 2x\pm y-1=0 $

C) $ x\pm 2y+1=0 $

D) $ x\pm 2y-1=0 $

Show Answer

Answer:

Correct Answer: A

Solution:

Tangent to $ y^{2}=8x $

therefore $ y=mx+\frac{2}{m} $

Tangent to $ \frac{x^{2}}{1}-\frac{y^{2}}{3}=1 $

therefore $ y=mx\pm \sqrt{m^{2}-3} $

On comparing, we get m = ±2 or tangent as