Question #b619a

1 Answer
Feb 3, 2018

theta=149.16^@, 210.84^@

Explanation:

All angles to 2 d.p in degrees.

0^@ < theta<=360^@
costheta=-0.8586

Use our calculator to find one value:

theta=cos^-1(-0.8586)
theta=149.16^@

We also know that costheta=cos(360^@-theta) You can verify this using the cos graph.

enter image source here
cos30=cos330 and cos60=cos300

:. cos149.16=cos(360-149.16)

theta=149.16^@, 210.84^@