Find an angle theta with 0 degree Solutiongiven theta sin20

Solution

given

theta = sin(200^o )

==> sin( 180 + 20 )

it is third quadrant , in this sin is negative

==> - sin( 20 )

==> - 0. 34

theta = cos( 200)

==> cos( 180 + 20 )

===> - cos20

==> -0.9396 degrees