question_answer

Find the value of \[\frac{5\,\sin 75{}^\circ \sin 77{}^\circ +2\cos 13{}^\circ \cos 15{}^\circ }{\cos 15{}^\circ \sin 77{}^\circ }-\frac{7\sin 81{}^\circ }{\cos 9{}^\circ }\]

A)  \[-\,1\]                         

B)  0

C)  1                                

D)  2

E)  None of these