Answer:
[tex] \sin( - 120) + \cos( - 120) \\ \\ = - \frac{ \sqrt{3} }{2} + ( - 0.5) \\ \\ = - \frac{ \sqrt{3} }{2} - \frac{1}{2} \\ \\ = { \boxed{ - ( \frac{1 + \sqrt{3} }{2}) }}[/tex]
Answer: -1.366
