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Question 6 - CBSE Class 12 Sample Paper for 2020 Boards - Solutions of Sample Papers and Past Year Papers - for Class 12 Boards

Last updated at Dec. 16, 2024 by Teachoo

If sin -1 x + sin -1 ⁡ y = 2π/3, then the value of cos -1 ⁡x + cos -1 ⁡y is

(a) 2π/3                 (b)  π/3              (c) π/2              (d) π

Transcript

Question 6 If sin^(−1)⁡𝑥+sin^(−1)⁡𝑦=2𝜋/3, then the value of cos^(−1)⁡𝑥+cos^(−1)⁡𝑦 is (a) 2𝜋/3 (b) 𝜋/3 (c) 𝜋/2 (d) 𝜋 We know that cos^(−1)⁡𝑥+sin^(−1)⁡𝑥=𝜋/2 And similarly cos^(−1)⁡𝑦+sin^(−1)⁡𝑦=𝜋/2 Adding both equations cos^(−1)⁡𝑥+sin^(−1)⁡𝑥+cos^(−1)⁡𝑦+sin^(−1)⁡𝑦=𝜋/2+𝜋/2 cos^(−1)⁡𝑥+cos^(−1)⁡𝑦+〖𝒔𝒊𝒏〗^(−𝟏)⁡𝒙+〖𝒔𝒊𝒏〗^(−𝟏)⁡𝒚=𝜋 Putting value of 〖𝑠𝑖𝑛〗^(−1)⁡𝑥+〖𝑠𝑖𝑛〗^(−1)⁡𝑦=2𝜋/3 〖𝑐𝑜𝑠〗^(−1)⁡𝑥+〖𝑐𝑜𝑠〗^(−1)⁡𝑦+2𝜋/3=𝜋 〖𝑐𝑜𝑠〗^(−1)⁡𝑥+〖𝑐𝑜𝑠〗^(−1)⁡𝑦=𝜋−2𝜋/3 〖𝑐𝑜𝑠〗^(−1)⁡𝑥+〖𝑐𝑜𝑠〗^(−1)⁡𝑦=𝜋/3 So, the correct answer is (b) - 𝝅/𝟑 1 mark
  1. Class 12
  2. Solutions of Sample Papers and Past Year Papers - for Class 12 Boards

    3. CBSE Class 12 Sample Paper for 2020 Boards

    CBSE Class 12 Sample Paper for 2019 Boards →
CBSE Class 12 Sample Paper for 2019 Boards →
Class 12
Solutions of Sample Papers and Past Year Papers - for Class 12 Boards

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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 14 years. He provides courses for Maths, Science and Computer Science at Teachoo