Na 8 1 of 4 Written Practice over 6.6-6.7 1. If tan O = 4, and O lies in quadrant III, find: a) Sin 20 b) cos 20 c) sin () d) cos () 2. Use half-angle formulas to find the exact values of: Tan () = tan(6 A= 30 "2) = tan (750) = tan (30+45. ) tan 18 + 7 - tun 30 + tonys + 1 1 - tan 45 stan30 ' tank iz ) = = 2+ V3 = 3.7:3205 3. Find the exact value of each of the following: a) Sin [2tan ] (-2)] b) tan [2cos-] (- =)] Solve the equation on the interval OS O S 2nt. 4. Cos (20) + 5cos 0 + 3 = 0 Cos(20)= Cas 20 - Sin20 = Cas?0- (1- cos30) CO2 20 = 2 cos 2 4- 1 2 cos ?8 - 1+5 cost +3= 0 2cos?# + 5 cost