$\cos(A) + \cos( B ) + \cos(C) \\ = 2 \cos( \frac{A + B}{2} ) \cos( \frac{ A- B}{2} ) + 1 - 2 { \sin }^{2} \frac{C}{2} \\ = 1 + 2\cos( \frac{\pi - C}{2} ) \cos( \frac{A - B}{2} ) - 2 { \sin }^{2} \frac{C}{2} \\ = 1 + 2 \sin \frac{C}{2} \cos( \frac{A - B}{2} ) - 2 { \sin }^{2} \frac{C}{2} \\ = 1 + 2 \sin \frac{C}{2} [ \cos( \frac{A - B}{2} ) - \sin \frac{C}{2}] \\ = 1 + 2 \sin \frac{C}{2} [ \cos( \frac{A - B}{2} ) - \cos( \frac{A + B}{2} )] \\ = 1 + 2 \sin\frac{C}{2} \times 2 \sin( \frac{ \frac{A + B}{2} +\frac{A - B}{2} }{2} ) \sin( \frac{ \frac{A + B}{2} - \frac{A - B}{2} }{2} ) \\ = 1 + 4 \sin \frac{A}{2} \sin \frac{B}{2} \sin \frac{C}{2}$

6 0

3 years ago

A machine makes 300 boxes in 15 minutes. Which expression equals the unit rate in boxes per minute

sukhopar [10]

Answer:

300*15

Step-by-step explanation:

thats it

7 0

3 years ago

Read 2 more answers

4.Rebecca biked 4.5 miles today and 3.2 miles

Fudgin [204]

Answer:

10-(4.5+3.2)

= 10-7.7

=2.3 miles

6 0

3 years ago

J/2--12=15 <br> j/2 is a fraction

Natasha_Volkova [10]

Answer:

j = 54

Step-by-step explanation:

j/2 - 12 = 15

j/2 = 15 +12

j/2 *2 = 27 * 2

j = 54

If you're kind enough, please mark this as the brainlist answer!

3 0

3 years ago