These formulas are found from taking the square root of the power reduction formulas and substitute for 0 sin = ±₁ tan 1-cose 2 COS 0 1- cos 0 sin 0 The tangent half angle formulas can be found by taking the quotient of the half-angle formulas of sine and cosine, then rationalize the numerator or denominator. tan |= ±₂ 1+ cos 0 2 0 (₁ sin 1+ cos 0 99 A If cos A = with 270°

5.using your calculator, determine sin2 + cos3 – tan4.

The question says: "Find sin(x/2), cos(x/2) and tan(x/2) from the given information: cscX=3, 90degrees < x < 180degrees."   For sin(x/2), I got the answer (Sqrt)((3-2(sqrt)2)/6). The answer guide in the text says that it should be a "3+2," but I wanted to see why that is.   I am trying to find tan(x/2) using sin(x/2)/cos(x/2), and I am having some trouble after the second step, with canceling the radicals...