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  1. x, y be two acute angles, x + y < 90° and sin(2x – 20°) = cos (2y + 20°), the value of tan (x + y) is
    1. 3
    2. 1
      3
    3. 1
    4. 2 + √2
Correct Option: C

sin (2x – 20°) = cos (2y + 20°)
⇒  sin (2x – 20°)
= sin {90° – (2y + 20°)}
⇒  2x – 20° = 90° – 2y – 20°
⇒  2x + 2y = 90°
⇒  2 (x + y) = 90° ⇒ x + y = 45°
∴  tan (x + y) = tan 45° = 1



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