2 os lcos340 04 01300 04 x4 21 Solution1 4 cos2 theta 2 cos
     2 os\' lcos-340 04 01300 04 x4 21  
  
  Solution
1) 4 cos^2 theta - 2 cos theta = 0
taking 2 cos theta as gcf
2 cos theta ( 2 cos theta -1 ) = 0
2 cos theta = 0 , 2 cos theta -1 = 0
cos theta = 1/2 , cos theta = 0
solutions in the range [ 0, 2pi ] is
theta = pi/3 , 5pi/3 , 3pi/2 , pi/2
2) 4 csc^2 theta + 12 csc theta +8 = 0
factoring the equation
4 ( csc^2 theta + 3 csc theta + 2 ) = 0
4 ( csc theta + 2) ( csc theta + 1 ) = 0
csc theta = -2 , csc theta = -1
solution in the range [ 0,2pi ] are
theta = 7pi/6 , 3pi/2

