Question

Find the value of cos 570° sin 510° + sin (-330°) cos (-390°).

Answer 1

Answer:

Cos 570 sin510+ sin(-330) cos (390) = LHS = O Cos (360+ 210) sin(360+ $50) - sin 330° 390" = Cos210's in 150° - sin (360-30°) Cas (360 +30°) Cos (180+30) Sin (180-30°) -(-Sin 30) Cas 30° = = cr³30² //in 30° + sin 30 cos 30°

Here we used (1) cos(-0) = coso (2) sin(-0)=sin (3) cos (360+ 0) = Coso (4) sin (360+ 0) = sin o sin (360-8)= -sino 6) cos (180 + 0) == caso sin (1-0) sin o

Answer 2

✦✧✧ Answer ✧✧✦

$( - 330°) \times \cos( - 390°) \\ - 330° \times \frac{ \sqrt{3} }{2} \\ - 165° \times \sqrt{3}$