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AP EAMCET · Maths · Hyperbola

The equation of the common tangent drawn to the curves \(y^2=8 x\) and \(x y=-1\) is

  1. A \(y = 2x + 1\)
  2. B \(2y = x + 6\)
  3. C \(y = x + 2\)
  4. D \(3y = 8x + 2\)
Verified Solution

Answer & Solution

Correct Answer

(C) \(y = x + 2\)

Step-by-step Solution

Detailed explanation

Let \(P\left(t, \frac{-1}{t}\right)\) be a point on \(x y=-1\) Equation of tangent of \(P\) \(\begin{aligned} & =\frac{1}{2}\left[x\left(\frac{-1}{t}\right)+x y\right]=-1-x+t^2 y=-2 t \\ & y=\frac{x}{t^2}+\frac{2}{t} \end{aligned}\) This is also at tangent of \(y^2=8 x\)…