Question

Calculați a) sin 30 grade cos 60 grade +sin 60 grade cos 30 grade
B)cos 60 grade cos 30grade -sin 60 grade sin 30 grade
C)COS 60grade -cos la a 2a 30grade +sin la a 2a 30 grade
D)sin 60 grade - 2 sin 30grade cos 30grade

Answer 1

a)$\frac{1}{2} * \frac{1}{2} + \frac{ \sqrt{3} }{2} * \frac{ \sqrt{3} }{2} = \frac{1}{4} + \frac{3}{4} = \frac{4}{4} = 1$

b)$\frac{1}{2} * \frac{ \sqrt{3} }{2} - \frac{ \sqrt{3} }{2} * \frac{1}{2} = \frac{ \sqrt{3} }{4} - \frac{ \sqrt{3} }{4} = 0$

c) $\frac{1}{2} - (\frac{ \sqrt{3} }{2} )^{2} + ( \frac{1}{2} )^{2} = \frac{1}{2} - \frac{3}{4} + \frac{1}{4} = \frac{1}{2} - 1 = - \frac{1}{2}$

d)sin60 - 2sin30= $\frac{ \sqrt{3} }{2} - 2* \frac{1}{2} = \frac{ \sqrt{3} }{2} - 1 = \frac{ \sqrt{3}-1 }{2}$