PLEASE HELP ASAP

1 answer:

3 0

<span>Real numbers are "closed" under addition Integers are "not closed" under division. Irrational numbers are "not closed" under multiplication. Rational numbers are "closed" under subtraction. If an operation is closed under a set of numbers that means that the result of the operation will always be within that same set of numbers. If that's not true, then the operation is not closed. So with that in mind, let's look at the problems. Real numbers are (closed,not closed) under addition * Since a real number plus a real number always results in another real number, then real numbers are closed under addition. So the answer is "closed" Integers are ( closed, not closed) under division. * Let's try this counter example. 1 divided by 2 = 1/2. 1/2 is NOT an integer, therefore integers are not closed under division. The answer is "not closed" Irrational numbers are (closed, not closed) under multiplication. * This is a tricky one. You may give an impulsive answer and say "closed". After all, how could you possibly multiply one non repeating infinite sequence by another and get something rational?. But what's pi multiplied by the reciprocal of pi? Both pi and 1/pi are irrational. Yet when you multiply them together you get 1 which is quite rational. So the answer is "not closed" Rational numbers are ( closed, not closed) under subtraction. * Since rational numbers are all numbers that can be expressed as a fraction consisting on an integer numerator and divisor, we can express subtraction as a/b - c/d = ad/bd - bc/bd = (ad-bc)/bd and since all we're doing is adding, subtracting, and multiplying integers which is closed under those operations, that means that rational numbers are also closed under subtraction. So the answer is "closed".</span>

You might be interested in

COMPLETE<br> Find the value of the function for O.<br> sin(45°) = ?

geniusboy [140]

Answer: $\sqrt{2}/2$ which is Choice B

This is the same as writing $\frac{\sqrt{2}}{2}$

The second "2" is not under or inside the square root.

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

Explanation:

Refer to the unit circle below. I've highlighted the angle 45 degrees and its corresponding sine value. It's the y coordinate of the point on the unit circle, for this particular angle.

Therefore, $\sin(45^{\circ}) = \frac{\sqrt{2}}{2}$

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

You could alternatively draw out a 45-45-90 triangle. Let x be the leg length and the hypotenuse is 1 unit long. Solve $x^2+x^2 = 1$ for x and you should get $x = \frac{\sqrt{2}}{2}$ as the length of each leg.

Then take the ratio of the opposite over hypotenuse to find the same answer mentioned above.

6 0

1 year ago

Assume that the sales of a certain appliance dealer can be approximaed y sraig were $6000 in 1982 and $ 64,000 in 1987. Let x -

viktelen [127]

Answer:

$y=11,600x+6,000$

Yearly sales in 1990: $98,800.

Step-by-step explanation:

We have been given that the sales of a certain appliance dealer can be approximated by a straight line. Sales were $6000 in 1982 and $ 64,000 in 1987.

If at 1982, $x=0$ then at 1987 x will be 5.