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sin (45° + θ) – cos (45° – θ) is equal to
(A) 2cosθ        (B) 0                (C) 2sinθ         (D) 1

Answers (1)

Answer.     [B]                  
Solution.    Here

:\sin \left ( 45^{\circ}+\theta \right )-\cos \left ( 45^{\circ}-\theta \right )
  Sin[90° - (45°- θ)] – cos(45°- θ)  
\left [ \because \left ( 45^{\circ} +\theta \right ) = \left ( 90^{\circ}-\left ( 45-\theta \right ) \right )\right ]           
  Cos(45°- θ) – cos(45°- θ)         [\because sin (90 – θ) = cosθ]
= 0
Hence option (B) is correct

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