Ответ:

[tex] \frac{ \sqrt{3} }{2} \sin(a) + \cos(a - \frac{\pi}{3} ) [/tex]

[tex] \frac{ \sqrt{3} \sin(a) }{2} + \cos(a - \frac{\pi}{3} ) [/tex]

[tex] \frac{ \sqrt{3} \sin(a) }{2} + \cos(a) \cos( \frac{\pi}{3} ) + \sin(a) \sin( \frac{\pi}{3} ) [/tex]

[tex] \frac{ \sqrt{3} \sin(a) }{2} + \cos(a) \times \frac{1}{2} + \sin(a) \sin( \frac{\pi}{3} ) [/tex]

[tex] \frac{ \sqrt{3} \sin(a) }{2} + \cos(a) \times \frac{1}{2} + \sin(a) \times \frac{ \sqrt{3} }{2} [/tex]

[tex] \frac{ \sqrt{3} \sin(a) }{2} + \frac{ \cos(a) }{2} + \sin(a) \times \frac{ \sqrt{3} }{2} [/tex]

[tex] \frac{ \sqrt{3} \sin(a) }{2} + \frac{ \cos(a) }{2} + \frac{ \sqrt{3} \sin(a) }{2} [/tex]

[tex] \sqrt{3} \sin(a) + \frac{ \cos(a) }{2} [/tex]