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  1. If sin α sec (30° + α) = 1 (0 < a < 60°), then the value of sin α + cos 2α is
    1. 1
    2. 2+√3
      2√3
    3. 0
    4. 2
Correct Option: A

sinα
= 1
cos(30° + α)

sinα
= 1
sin(90° - 30 - α)

sinα
= 1
sin(60° - α)

⇒ sin α = sin (60° – α)
⇒ 2α = 60° ⇒ α = 30°
∴ sinα + cos 2α
= sin 30° + cos 60°
=
1
+
1
= 1
22



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