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

(a) 0        (b) 1          (c) 2/√3        (d) not defined

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

Question 5 - CBSE Class 10 Sample Paper for 2020 Boards - Maths Standard - Part 2

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Question 5 If triangle ABC is right angled at C, then the value of sec (A + B) is (a) 0 (b) 1 (c) 2/√3 (d) not defined In Δ ABC Sum of angles = 180° ∠ A + ∠ B + ∠ C = 180° Given Δ ABC is right angled at C, So, ∠ C = 90° Therefore, our equation becomes ∠ A + ∠ B + 90° = 180° ∠ A + ∠ B = 180° – 90° ∠ A + ∠ B = 90° Now, sec (A + B) = sec 90° = 1/cos⁡〖90°〗 = 1/0 = Not defined ∴ Correct answer is option (d)

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Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.