gaokao 2015 Q12

gaokao · China · beijing-science Sine and Cosine Rules Determine an angle or side from a trigonometric identity/equation

12. In $\triangle A B C$, $a = 4 , b = 5 , c = 6$, then $\frac { \sin 2 A } { \sin C } =$ $\_\_\_\_$.

12. In $\triangle A B C$, $a = 4 , b = 5 , c = 6$, then $\frac { \sin 2 A } { \sin C } =$ $\_\_\_\_$.