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2 years ago

Question 12. Is the one I need help on

Mathematics

1 answer:

Mekhanik [1.2K]2 years ago

6 0

Four Answers:

Choice A
Choice C
Choice D
Choice J

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Explanation:

A rational number is any fraction of two whole numbers.

Examples: 7/9 and -8/12

This can be extended to some numbers like $\sqrt{49}$ because

$\sqrt{49} = \sqrt{7^2} = 7 = \frac{7}{1}$

As you can see, any whole number is also rational but not the other way around.

So far, these examples help show that choices A, C, D, and J are rational numbers. Choice D might need a bit of rewriting like so:

$\frac{0.5}{8} = 0.5 \div 8\\\\ = \frac{1}{2} \div \frac{1}{8} \\\\= \frac{1}{2} \times \frac{8}{1}\\\\ = \frac{8}{2}\\\\ = 4$

In short, the expression for choice D simplifies to 4 = 4/1 showing that is rational. Or you can use the shortcut that rational/rational = rational.

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A number like $\sqrt{13}$ is NOT rational because the 13 is not a perfect square. There's no way to rewrite that square root as a ratio or fraction of integers. This allows us to rule out choice B. Choices E, F, and G are eliminated for similar reasoning.

Choice H is ruled out because circle areas involve pi = 3.14159... which is famously an irrational number. The proof of which is very lengthy to go over, but the short version is the decimal digits go on forever without a pattern. This is an informal way to check if we have an irrational number.

Choice I is only eliminated if and only if the side lengths of the square are rational, and also when the side lengths are whole numbers. Its not clear what your teacher's intentions here are, but I'll assume this is the case.

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To summarize, we eliminated B, E, F, G, H, I

We're left with A, C, D, J as the final answers. They either can be written as fractions of integers, or already are fractions of integers.

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. For each of these intervals, list all its elements or explain why it is empty. a) [a, a] b) [a, a) c) (a, a] d) (a, a) e) (a,

Eva8 [605]

Answer:

Elements are of the form

(i) $[a,a]=\{[x,y] : a\leq x\leq a, a\leq y\leq a; a\in \mathbb R\}$

(ii) $[a,b)=\{[x,y) :a\leq x$

(iii) $(a,a]=\{(x,y] :a$

(iv) $(a,a)=\{(x,y): a$

(v) (a,b) where a>b= $\{(x,y) : a>x>b,a>y>b;a>b,a,b \in \mathbb R\}$

(vi) [a,b] where a>b= $\{[x,y] : a\geq x\geq b,a\geq y\geq b;a>b,a,b \in \mathbb R\}$

Step-by-step explanation:

Given intervals are,

(i) [a,a] (ii) [a,a) (iii) (a,a] (iv) (a,a) (v) (a,b) where a>b (vi) [a,b] where a>b.

To show all its elements,

(i) [a,a]

Imply the set including aa from left as well as right side.

Its elements are of the form.

$\{[a,a] : a\in \mathbb R\}=\{[0,0],[1, 1],[-1,-1],[2,2],[-2,-2],[3,3],[-3,-3],........\}$

Since there is a singleton element a of real numbers, this set is empty.

Because there is no increment so if $a\in \mathbb R$ then the set [a,a] represents singleton sets, and singleton sets are empty so is [a,a].

(ii) [a,a)

This means given interval containing a by left and exclude a by right.

Its elements are of the form.

$[ 1, 1),[-1,-1),[2,2),[-2,-2),[3,3),[-3,-3),........$

Since there is a singleton element a of real numbers withis the set, this set is empty.

Because there is no increment so if $a\in \mathbb R$ then the set [a,a) represents singleton sets, and singleton sets are empty so is [a.a).

(iii) (a,a]

It means the interval not taking a by left and include a by right.

Its elements are of the form.

$( 1, 1],(-1,-1],(2,2],(-2,-2],(3,3],(-3,-3],........$

Since there is a singleton element a of real numbers, this set is empty.

Because there is no increment so if $a\in \mathbb R$ then the set (a,a] represents singleton sets, and singleton sets are empty so is (a,a].

(iv) (a,a)

Means given set excluding a by left as well as right.

Since there is a singleton element a of real numbers, this set is empty.

Its elements are of the form.

$( 1, 1),(-1,-1],(2,2],(-2,-2],(3,3],(-3,-3],........$

Because there is no increment so if $a\in \mathbb R$ then the set (a,a) represents singleton sets, and singleton sets are empty, so is (a,a).

(v) (a,b) where a>b.

Which indicate the interval containing a, b such that increment of x is always greater than increment of y which not take x and y by any side of the interval.

That is the graph is bounded by value of a and it contains elements like it we fixed a=5 then,

$(a,b)=\{(5,0),(5,1),(5,2).....\}$ e.t.c

So this set is connected and we know singletons are connected in $\mathbb R$ . Hence given set is empty.

(vi) [a,b] where $a\leq b$ .

Which indicate the interval containing a, b such that increment of x is always greater than increment of y which include both x and y.

That is the graph is bounded by value of a and it contains elements like it we fixed a=5 then,

$[a,b]=\{[5,0],[5,1],[5,2].....\}$ e.t.c

So this set is connected and we know singletons are connected in $\mathbb R$ . Hence given set is empty.

8 0

3 years ago

A- y= -3/2x+8 B- y=3/2x+5 C- y=2/3x+8 D- y=-2/3x+5

Annette [7]

Answer:

I think the right answer is B.

4 0

3 years ago

Which graph shows rotational symmetry?

mihalych1998 [28]

Answer:

Step-by-step explanation:

4 0

3 years ago

Read 2 more answers

Ella has 0.5 lbs of sugar. How much water should she add to make the following concentrations? Tell Ella how much syrup she will

Vadim26 [7]

Answer:

1) 2 lbs

2) 0.17 lbs

3) 9.5 lbs

Step-by-step explanation:

Amount of sugar Ella has = 0.5 lbs

Let the amount of water she adds to make the solution = x lbs

So total amount of the mixture would be = (x + 0.5) lbs

Case 1: 20% syrup

20% syrup means the sugar percentage in the mixture should be 20% of the entire mixture. So, 0.5 should be 20% of (x + 0.5). In equation form this can be written as:

0.5 = 20% of (x + 0.5)

0.5 = 0.2(x + 0.5)

Dividing both sides by 0.2, we get:

2.5 = x + 0.5

x = 2 lbs

This means, 2 lbs of water should be added to make 20% syrup solution. So, total syrup she would have will be 2.5 lbs.

Case 2: 75% syrup

75% syrup means the sugar percentage in the mixture should be 75% of the entire mixture. So, 0.5 should be 75% of (x + 0.5). In equation form this can be written as:

0.5 = 75% of (x + 0.5)

0.5 = 0.75(x + 0.5)

Dividing both sides by 0.75, we get:

0.67 = x + 0.5

x = 0.17 lbs

This means, 0.17 lbs of water should be added to make 75% syrup solution. So, total syrup she would have will be 0.67 lbs.

Case 3: 5% syrup

5% syrup means the sugar percentage in the mixture should be 5% of the entire mixture. So, 0.5 should be 5% of (x + 0.5). In equation form this can be written as:

0.5 = 5% of (x + 0.5)

0.5 = 0.05(x + 0.5)

Dividing both sides by 0.05, we get:

10 = x + 0.5

x = 9.5 lbs

This means, 9.5 lbs of water should be added to make 5% syrup solution. So, total syrup she would have will be 10 lbs.

3 0

3 years ago

This is hard please help!!!

liq [111]

Answer:

6 and 1/3

Step-by-step explanation:

the only thing gets reduced is the fraction part and 5 and 15 have common numbers in 5 5 goes into 5 one time and 5 goes into 15 3 times. so it's 6 1/3

4 0

2 years ago