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murzikaleks [220]
3 years ago
14

If it is possible to label each element of an infinite set S with a finite string of keyboard characters, from a finite list cha

racters, where no two elements of Shave the same label, then S is a countably infinite set. Use the above statement and prove that the set of rational numbers is countable.
A. We can label the rational numbers with strings from the set (0, 1, 2, 3, 4, 5, 6, 7, 8, 9,-) by writing down the string that represents that rational number in its simplest form. As the labels are unique, it follows that the set of rational numbers is countable.
B. We can label the rational numbers with strings from the set {0, 1, 2, 3, 4, 5, 6, 7, 8, 9,/,-) by writing down the string that represents that rational number in its simplest form. As the labels are unique, it follows that the set of rational numbers is countable.
C. We can label the rational numbers with strings from the set (0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 1) by writing down the string that represents that rational number in its simplest form. As the labels are unique, it follows that the set of rational numbers is countable.
D. We can label the rational numbers with strings from the set (1, 2, 3, 4, 5, 6, 7, 8, 9,/ -) by writing down the string that represents that rational number in its simplest form. As the labels are unique, it follows that the set of rational numbers is countable.
Mathematics
1 answer:
adelina 88 [10]3 years ago
6 0

Answer:

D. We can label the rational numbers with strings from the set (1, 2, 3, 4, 5, 6, 7, 8, 9, / -) by writing down the string that represents that rational number in its simplest form. As the labels are unique, it follows that the set of rational numbers is countable.

Step-by-step explanation:

The label numbers are rational if they are integers. The whole number subset is rational which is written by the string. The sets of numbers are represented in its simplest forms. The rational numbers then forms numbers sets which are countable.

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Use a z-Table to determine the percent of data specified.
kobusy [5.1K]
I think c I might be wrong tho :)
4 0
3 years ago
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The DVD player shows the time of day as 1:43.
steposvetlana [31]

Answer:

The answer is 2:36

Step-by-step explanation:

The answer is 2:36 because 1:43 plus 56 minutes later would be 2:36

3 0
3 years ago
A. Find the amplitude.
Feliz [49]

Answers:

  • a) Amplitude = 2
  • b) Period = pi
  • c) Vertical shift = -2, which means it has been shifted down 2 units.
  • d) Horizontal shift = 3pi/8, this shifting is to the right.
  • e) There is <u>  one  </u> cycle between 0 and 2pi.
  • f) The equation of the graph is y = 2*sin(2(x-3pi/8))-2

========================================================

Explanations:

Part (a)

The highest point is when y = 0 and the lowest point is when y = -4. The vertical distance between the peak and valley is 4 units, which cuts in half to 2. This is the amplitude. It's the vertical distance from the center to either the peak or valley.

Note: Amplitude is always positive as it measures a distance.

---------------------

Part (b)

For x > 0, the first valley or lowest point occurs between 0 and pi/4. It appears to be the midpoint of the two values. So that would be (0+pi/4)/2 = pi/8.

The next valley occurs between pi and 5pi/4. Compute the midpoint to get (pi+5pi/4)/2 = (4pi/4+5pi/4)/2 = (9pi/4)/2 = 9pi/8

So we have the graph go from one valley x = pi/8 to the next valley over x = 9pi/8. This is a distance of pi units because 9pi/8-pi/8 = 8pi/8 = pi

The graph repeats itself every pi units, so the period is pi.

---------------------

Part (c)

The midline is normally through y = 0, aka the x axis. However, the graph shows the midline is through y = -2. This means the graph has been shifted down 2 units.

---------------------

Part (d)

This will depend on whether you use sine or cosine. This is entirely because cosine is a phase-shifted version of sine, and vice versa. I'll go with sine.

The parent sine function y = sin(x) goes through the origin (0,0)

However, as part (c) mentioned, we shifted the graph 2 units down. So we have y = sin(x)-2. But plugging x = 0 into this leads to the point (0,-2)

This doesn't match what the graph says. The graph shows the point (3pi/8, -2) on the red curve. The x coordinate 3pi/8 is the midpoint of pi/4 and pi/2

This must mean we need to shift the sine graph 3pi/8 units to the right.

---------------------

Part (e)

Start at the lowest point when x = pi/8. If you start the cycle here, then it ends when x = 9pi/8. See part (b).

So far we've completed one cycle. If we start at x = 9pi/8, then the next valley or lowest point is slightly beyond or to the right of x = 2pi. This means we run out of room and we haven't completed a full cycle.

Overall, one full cycle is between 0 and 2pi.

---------------------

Part (f)

Again I'm going to use sine instead of cosine. Refer back to part (d).

The general sine curve equation is

y = A*sin(B(x-C))+D

where

  • |A| = amplitude
  • B handles the period, specifically T = 2pi/B where T is the period. We can solve for B to get B = 2pi/T
  • C = horizontal phase shift
  • D = vertical shift, and ties together with the midline equation

In this case, we found that

  • |A| = 2
  • T = pi leads to B = 2pi/T = 2pi/pi = 2
  • C = 3pi/8
  • D = -2

So,

y = A*sin(B(x-C))+D

will update to

y = 2*sin(2(x-3pi/8))-2

which is one way to express the equation of the red curve. Optionally you can distribute the 2 through to (x-3pi/8).

6 0
3 years ago
A trough is 10 ft long and its ends have the shape of isosceles triangles that are 4 ft across at the top and have a height of 1
Anna11 [10]

Answer:

7.5 ft³/min

Step-by-step explanation:

Let x be the depth below the surface of the water. The height, h of the water is thus h = 10 - x.

Now, the volume of water V = Ah where A = area of isosceles base of trough = 1/2bh' where b = base of triangle = 4 ft and h' = height of triangle = 1 ft. So, A = 1/2 × 4 ft × 1 ft = 2 ft²

So, V = Ah = 2h = 2(10 - x)

The rate of change of volume is thus

dV/dt = d[2(10 - x)]/dt = -2dx/dt

Since dV/dt = 15 ft³/min,

dx/dt = -(dV/dt)/2 = -15 ft³/min ÷ 2 = -7.5 ft³/min

Since the height of the water is h = 10 - x, the rate at which the water level is rising is dh/dt = d[10 - x]/dt

= -dx/dt

= -(-7.5 ft³/min)

= 7.5 ft³/min

And the height at this point when x = 8 inches = 8 in × 1 ft/12 in  = 0.67 ft is h = (10 - 0.67) ft = 9.33 ft

7 0
3 years ago
let m angle A = 40 degrees. If angle B is a complement of angle A and angle C is a supplement of angle B, find these measures
FinnZ [79.3K]
A= 40 B=50 C=130
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7 0
3 years ago
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