#1

#2**0 **

im very confused on how to solve for this one, could you check it out as well?

jjennylove
Feb 13, 2020

#4**+2 **

cos ( arcsin (-0.845))

Easy way :

arcsin (-0.845) = - 57.67°

cos (-57.67°) ≈ .535

"Expert" way

We are looking for the cosine of an angle whose sine = -845/ 1000 = y /r

Remember that cosine = x /r

We need to find x

x = ±√ [ r^2 - y^2] = ±√ [ 1000^2 - 845^2 ] = ±534.76 = ±535

This angle is in the 4th quadrant (the sine is negative there).....but the cosine is positive in this quadrant

So

cosine for this angle = x / r = 535 / 1000 = .535

CPhill Feb 13, 2020