a)[tex] \frac{1}{2} * \frac{1}{2} + \frac{ \sqrt{3} }{2} * \frac{ \sqrt{3} }{2} = \frac{1}{4} + \frac{3}{4} = \frac{4}{4} = 1[/tex]
b)[tex] \frac{1}{2} * \frac{ \sqrt{3} }{2} - \frac{ \sqrt{3} }{2} * \frac{1}{2} = \frac{ \sqrt{3} }{4} - \frac{ \sqrt{3} }{4} = 0[/tex]
c) [tex] \frac{1}{2} - (\frac{ \sqrt{3} }{2} )^{2} + ( \frac{1}{2} )^{2} = \frac{1}{2} - \frac{3}{4} + \frac{1}{4} = \frac{1}{2} - 1 = - \frac{1}{2} [/tex]
d)sin60 - 2sin30= [tex] \frac{ \sqrt{3} }{2} - 2* \frac{1}{2} = \frac{ \sqrt{3} }{2} - 1 = \frac{ \sqrt{3}-1 }{2} [/tex]
