Answer:
A + B + C = π ...... (1)
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L.H.S.
= ( cos A + cos B ) + cos C
= { 2 · cos[ ( A+B) / 2 ] · cos [ ( A-B) / 2 ] } + cos C
= { 2 · cos [ (π/2) - (C/2) ] · cos [ (A-B) / 2 ] } + cos C
= { 2 · sin( C/2 ) · cos [ (A-B) / 2 ] } + { 1 - 2 · sin² ( C/2 ) }
= 1 + 2 sin ( C/2 )· { cos [ (A -B) / 2 ] - sin ( C/2 ) }
= 1 + 2 sin ( C/2 )· { cos [ (A-B) / 2 ] - sin [ (π/2) - ( (A+B)/2 ) ] }
= 1 + 2 sin ( C/2 )· { cos [ (A-B) / 2 ] - cos [ (A+B)/ 2 ] }
= 1 + 2 sin ( C/2 )· 2 sin ( A/2 )· sin( B/2 ) ... ... ... (2)
= 1 + 4 sin(A/2) sin(B/2) sin(C/2)
= R.H.S. ............................. Q.E.D.
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In step (2), we used the Factorization formula
cos x - cos y = 2 sin [ (x+y)/2 ] · sin [ (y-x)/2 ]
Step-by-step explanation:
If Melanie get's 4.10$, then Jacob get's 20.50$.
We can divide to get the unit rate:
20.50 ÷ 4.10 = 5
This means that if Jacob gets 5$, then Melanie will get 1$.
So in this case, Melanie get's 1$.
That is the Identity Property of Addition.
If it is adding and the whole number stays the same it is Identity Property of Addition.
If it is multiplying then it would be the Identity Property of Multipulcation. For example for this problem it would be 6x1 in multipulcation in which the whole number would stay the same.
Here are descriptions of all the properties:
https://wikis.engrade.com/mathproperties1
Answer:

Step-by-step explanation:
Carlie is running two different business.
She needs to pay:
- For the childcare business,
100$ for the materials
12$ per hour for each associate for her childcare business, so if we call:
= the number of hours worked by each associate
= the number of associates
The total cost for the childcare business is:
(1)
- For the lawn care business,
275$ for the materials
10$ per hour for each associate for her lawn care business, so if we call:
= the number of hours worked by each associate
= the number of associates
The total cost for the lawn care business is:
(2)
Therefore, the total expenses from both businesses is the sum of (1) and (2):

Answer:
300 euros
Step-by-step explanation:
1200 x 5 x 5=30000/100=300