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If sec (A + B) = √2 and sin (A - B) = 1 then find the value of 2A + B?1. 112.5°2. 87.5°3. 92.5°4. 109.5° |
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Answer» Correct Answer - Option 1 : 112.5° Given: It is given that sec (A + B) = √2 and sin (A - B) = 1 Formula Used: Basic concept of trigonometric ratio and identities We know that Sec 45° = √2 and sin 90° = 1 Calculation: The equation sec (A + B) = √2 can be written as ∵ Sec 45° = √2 ∴ Sec (A + B) = Sec 45° ⇒ A + B = 45° ---(1) And sin (A - B) = 1 so it can be written as ∵ Sin 90° = 1 ∴ sin (A - B) = Sin 90° ⇒ A - B = 90° ---(2) By equation (1) and (2) we get ∴ A = 67.5° and B = -22.5 ° Now, we have to find the value of 2A + B ∴ 2 × 67.5 + (-22.5) = 112.5° Hence, option (1) is correct |
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