Math Chapter Wise Tangent, Normal, Increasing, Decreasing And Maxima/Minima Of A Function Of One Variable English MCQ Rajasthan TGT 2013 Q.If the line ax + by + c = 0 is normal to the curve xy = 1, then- Aab = 0 Bab < 0 Ca > 0, b > 0 Da < 0, b < 0 Show answer Correct answer: ab < 0