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[angela128]

\(\frac{sin115^ \circ * cos5^ \circ +cos115^ \circ *sin5^ \circ }{cos210^ \circ }\)

[eresh]

\(\frac{\sin 115^{\circ}\cdot \cos 5^{\circ}+\cos 115^{\circ}\cdot \sin 5^{\circ}}{\cos 210^{\circ}}=\\=\frac{\sin (115^{\circ}+5^{\circ})}{\cos (270^{\circ}-60^{\circ}}=\frac{\sin 120^{\circ}}{-\sin 60^{\circ}}=\frac{\sin (180^{\circ}-60^{\circ})}{-\sin 60^{\circ}}=\\=\frac{\sin 60^{\circ}}{-\sin 60^{\circ}}=-1\)