Answer:
1/2 is the pre image for this
Write the left side of the given expression as N/D, where
N = sinA - sin3A + sin5A - sin7A
D = cosA - cos3A - cos5A + cos7A
Therefore we want to show that N/D = cot2A.
We shall use these identities:
sin x - sin y = 2cos((x+y)/2)*sin((x-y)/2)
cos x - cos y = -2sin((x+y)/2)*sin((x-y)2)
N = -(sin7A - sinA) + sin5A - sin3A
= -2cos4A*sin3A + 2cos4A*sinA
= 2cos4A(sinA - sin3A)
= 2cos4A*2cos(2A)sin(-A)
= -4cos4A*cos2A*sinA
D = cos7A + cosA - (cos5A + cos3A)
= 2cos4A*cos3A - 2cos4A*cosA
= 2cos4A(cos3A - cosA)
= 2cos4A*(-2)sin2A*sinA
= -4cos4A*sin2A*sinA
Therefore
N/D = [-4cos4A*cos2A*sinA]/[-4cos4A*sin2A*sinA]
= cos2A/sin2A
= cot2A
This verifies the identity.
Answer:
Answer is 28/4 = 7
Step-by-step explanation:
Given
Beth B = 28 problem
B has 4 times more problem than Mery m
Find
Total number of problem Mery m has if Beth has 4 times more problem than Beth
So,
B = 4 x m
m = B/4 = 28/4 = 7
Finally answer (d) is correct which is 28 ÷ 4 = m
Answer:
a.
The lender made an excellent estimate; it was equal to the actual closing costs.
Step-by-step explanation: 100% on EDG. 2020
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