Answer:
x = 4 or x = 12
Step-by-step explanation:
Given:
y = -10x² + 160x - 430
When y = $50
50 = -10x² + 160x - 430
50 + 430 = -10x² + 160x
480 = -10x² + 160x
-10x² + 160x - 480 = 0
Divide through by -10
x² - 16x + 48 = 0
Solve the quadratic equation using factorization method
+48 = -12 × -4
-16 = -12 -4
Therefore,
-12 and -4 are both factors
x² - 16x + 48 = 0
(x - 4 )(x - 12 ) = 0
x - 4 = 0
x = 4
OR
x - 12 = 0
x = 12
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:
The correct answer is 15%
Source: Just took quiz and got it correct
Answer:
$51.30
Step-by-step explanation:
Add 32.50 + 15 to get 47.5.
Multiply 47.5 x 0.08 to get 3.8.
Add 3.8 to 47.5 to get $51.30.
40 is 41.6666666667% of 96
