Check sibling questions

If ∆ABC is right angled at C, then the value of cos (A + B) is

(A) 0   (B) 1   (C) 1/2    (D) √3/2

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Question 11 If ∆ABC is right angled at C, then the value of cos (A + B) is (A) 0 (B) 1 (C) 1/2 (D) √3/2 Given ∠ C = 90° Now, By Angle sum property in Δ ABC ∠ A + ∠ B + ∠ C = 180° ∠ A + ∠ B + 90° = 180° ∠ A + ∠ B = 180° − 90° ∠ A + ∠ B = 90° Now, cos (A + B) = cos 90° = 0 So, the correct answer is (A)

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Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 12 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.