Practicing Success
If A = 60°, what is the value of: $\frac{10 \sin \frac{A}{2}+8 \cos A}{7 \sin \frac{3 A}{2}-12 \cos A} ?$ |
10 12 9 7 |
9 |
$\frac{10 \sin \frac{A}{2}+8 \cos A}{7 \sin \frac{3 A}{2}-12 \cos A} $ A = 60° 10 sin \(\frac{A}{2}\) + 8 cosA = 10 × sin 30° + 8 cos 60° = 10 × \(\frac{1}{2}\) + 8× \(\frac{1}{2}\) = 9 & 7 sin \(\frac{3A}{2}\) - 12 cosA = 7 sin 90° - 12 cos60° Now , $\frac{10 \sin \frac{A}{2}+8 \cos A}{7 \sin \frac{3 A}{2}-12 \cos A} $ = 9 |