Answer:
Step-by-step explanation:
we know that
The number of kWh of energy that the model house generate per year is given by the sum of kWh of energy generates by the windmills multiplied by the number of windmills, plus the kWh of energy generates by the solar panels multiplied by the number of solar panels.
so
For 10 year
Multiply the expression above by 10
Apply distributive property
10.5x = 7.5x + 30
10.5x - 7.5x = 30
3x = 30
x = 30/3
x = 10
10.5(10) = 105
7.5(10) + 30 = 75 + 30 = 105
they need to purchase 10 t-shirts from each company for a total of $105 for each company
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:
Answer:
The answer is A
Step-by-step explanation:
