1) cos (150°)=- cos(180°-150°) = - cos(30°) and - cos30° = - √(3) / 2
sin(150°) = sin(180°-150°) =sin30. and sin30° = 1/2
Then : 5/2(cos 150° + i sin 150°) becomes : 5/2{(-√(3) /2 + I (1/2)]
OR 5/4( - √3 + i)
let's recall that d = rt, distance = rate * time.
we know that Steve is twice as fast as Jill, so say if Jill has a speed or rate of "r", then Steve is traveling at 2r fast, now we know they both in opposite directions have covered a total of 120 miles, so if Jill covered "d" miles then Steve covered 120 -d, check the picture below.
Answer:
2nd one
Step-by-step explanation: