Double and Half Angle Formulas Recall the double angle formulas: sin(2a) = 2 sin(a) cos(a) cos(2a) = cos (a) - sin?(a) = 1 - 2 sin?(a) = 2 cos?(a) - 1 tan(20) = 2 tan(a) 1 - tan?(a) Recall the half angle formulas: sin (? = +1 - cos(a) 2 cos ( = + 1 + cos(a) 2 1 - cos(a) tan (?) = + 1 + cos(a) Example: Since cos(#) = 2, get the cosine of # via the half-angle formula: cos = Cos #/4 =+1 1 + cos(#) 1+ 12 2 :+ V2 1 2+ V2 V2+ 12 N/N 2 Here, we used the '+' sign, because the angle = To = 22.50 is in the first quadrant, so that it's cosine is positive. Practice Use the half angle formulas to find the following trigonometric function values. a. sin () = b. tan ( 12) = C. cos ( 16) = Decimal approximations are not allowed for this problem. . Enter your answer in exact form. . Use "sqrt( )" to represent