Answer:
Explanation:
sin 300° = sin (300° - 360°) = sin (-60°) = -sin 60° = -(1/2)
cos 945° = cos (945° - 360°) = cos (585°) = cos (-295°) = -cos 295°
tan (-675°) = -tan (675° - 360°) = -tan 315°
so
sin 300° − cos 945° + tan(−675°) = -(1/2) - (-cos 295°) + (-tan 315°)
It is not a trivial task to simplify the above equations without using a calculator.
= -(1/2) + cos 295° + tan 315°
As we know that cos(x) = cos(360°-x) = -cos(x) and tan(x) = -tan(360°-x) = -tan(x)
= -(1/2) - cos 295° - tan 315°
As we know that cos(295°) = cos(360°-65°) = cos(65°) and tan(315°) = tan(360°-45°) = tan(45°)
= -(1/2) - cos(65°) - tan(45°)
= -(1/2) - 0.4226 - 1
= -0.5 - 0.4226 - 1
= -1.4226
.