Chapter 5 - Section 5.4 - Half-Angle Formulas - 5.4 Problem Set - Page 304: 6

False

Testing the equation: $\cos{\dfrac{\theta}{2}} = \dfrac{1}{2} \cos{\theta}$ for $\theta = 60^\circ$ $LHS = \cos{30} = \dfrac{\sqrt{3}}{2}$ $RHS = \dfrac{1}{2} \cos{60} = \dfrac{1}{4}$ $RHS \neq LHS$ $\therefore \cos{\dfrac{\theta}{2}} \neq \dfrac{1}{2} \cos{\theta}$