Math Chapter Wise Trigonometrical Identities And Circular Function English MCQ PGT 2013 Q.In a triangle ABC ((()) 1 2absin 2 + − A B C is equation. Aa2 –b2 –c2 Bb2 –a2 –c2 Ca2 +b2 –c2 Da2 +b2 +c2 Show answer Correct answer: a2 +b2 –c2