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AP EAMCET · Maths · Pair of Lines

The lines \(a x^2+2 h x y+b y^2=0\) are at right angles if

  1. A \(a+b=0\)
  2. B \(a+b=1\)
  3. C \(h^2-a b=0\)
  4. D \(a=b\)
Verified Solution

Answer & Solution

Correct Answer

(A) \(a+b=0\)

Step-by-step Solution

Detailed explanation

The acute angle \((\theta)\) between lines represented by equation \(a x^2+2 h x y+b y^2=0\), is \(\theta=\tan ^{-1}\left(\frac{2 \sqrt{h^2-a b}}{|a+b|}\right)\) If lines are perpendicular then \(a+b=0\).