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Let's write the general form of the sine curve:
, where,
- A is the amplitude. Also, if A is negative, curve reflects about x axis
- B is the compression/stretching factor. It changes the period when it is a value other than 1.
- C is the phase shift. It translates curve left or right. Negative value shifts right and positive value shifts left.
- D is the vertical shift. It translates curve up or down. Negative value shifts down and positive value shifts up.
Let's check the 4 choices.
A.
Since this curve's A is -2, its amplitude is 2 and range is from -2 to 2. BUT since D value is -3, it shifts vertically 3 units down making the range from -1 to -5. Clearly choice A is not true.
B.
This graph is the graph of
shifted 3 units DOWN since D is negative. This choice isn't true.
C.
Because of the - (minus) sign in front of the function, the function is reflected about x-axis, but amplitude doesn't change. Since A value is 2, amplitude is 2. This is true.
D.
Period depends on the B value. Here, B value is 1, so period is normal as the parent function of a sine curve, which is
, NOT
. So this is not correct.
ANSWER: C is true
Step-by-step explanation:
an arithmetic sequence means that every new term is the old term plus a constant number.
in our case that constant is +50.
and our starting value a0 = 250
so, the first 4 terms are
$250, $300, $350, $400
for the function formula we know
a0 = $250
a1 = a0 + 50 = 250 + 50 = $300
a2 = a1 + 50 = a0 + 50 + 50 = a0 + 2×50 = $350
a3 = a2 + 50 = a0 + 3×50 = $400
so, we see
an = a0 + n×50 = 250 + 50n
therefore,
f(n) = 250 + 50n
after 9 months saving we reached a9, meaning n=9.
f(9) = 250 + 50×9 = 250 + 450 = $700
The area of the pond is
Area = l * w
Area = 50 * 50
Area = 2500 square meters.
Then there is a sidewalk with 5 meters wide around the pond.
So the new dimension is
60 * 60
Area = 60 * 60
Area = 3600
Then at 45 m^2 = $74
= 3600 / 45 * 74
= $5,920
So the total cost of tile is $5,920.