Question

Calculate the expressions :
sin15° + sin75° - cos 15° - cos 75° + sin 30°
Help me plz !!! Thanks

Answer 1

Step-by-step explanation:

sin15° + sin75° - cos 15° - cos 75° + sin 30°

= sin15° + sin75° - sin (90°-15°) - sin (90°-75°) + sin 30°

= sin15° + sin75° - sin 75° - sin 15° + sin 30°

= sin 30°

$= \frac{1}{2} \\ \because \: sin \: (90 \degree \: - \theta) = cos \: \theta$