Let U be a matrix where u_ij = 0 if i > j, and L be a matrix where l_ij = 0 if i < j.
(a) U is called an upper triangular matrix and L is a lower tri-angular matrix. Explain why.
(b) Prove or disprove: The sum of two upper triangular matrices is an upper triangular matrix.
(c) Prove or disprove: The product of two upper triangular matrices is an upper triangular matrix.

Answer:

True

Step-by-step explanation:

Answer is true, the degree of a function tells you at most how many zeroes the function can have.

Answer for this prob

Answer:

Option A i the right option.

First blank is 110-[tex]10\sqrt{61}[/tex] or 10(11-[tex]\sqrt{61}[/tex])

Second blank is 31.898

Let me know if anything didn't make sense.  

Step-by-step explanation:

So a diagonal through a rectangle makes two triangles.  The question wants to know how much walking is saved walking down the diagonal  vs walking along two sides that make the diagonal.  in this case the two non diagonal sides walked are 60 paces and 50 paces.

A diagonal through a rectangle specifically makes a right triangle, so to find the diagonal we can use the pythagorean theorem.  

c^2 = 60^2 + 50^2

c = [tex]\sqrt{60^2 + 50^2}[/tex]

c = [tex]\sqrt{6100} = 10\sqrt{61}[/tex]

if you don't get how to simplify a radical like that let me know.

Anyway, looking at the answers you can see right away the second option says no approximation is necessary.  Well, you need to approximate square root of 61, so we can say the second answer is not right.  So now we need to know what to fill in for option 1.

it wants the distance saved, well we know the distance of the diagonal is [tex]10\sqrt{61}[/tex]  Hopefully you can see the disctance walking the two other sides is just adding them up so 50+60=110.

Now, to find the difference, that is subtraction.  So subtract the smaller number from the larger number.  You do need to remember with a right triangle, the sum of the to non diagonal (hypotenuse) sides are always longer than said hypotenuse.  so that's 110-[tex]10\sqrt{61}[/tex].  That is the exact form.  Or you could use 10(11-[tex]\sqrt{61}[/tex])  They are the same.

Then just plug that into a calculator for a decimal approximation.

Step-by-step explanation:

tan Z=p/b

=48/14

=24/7

Keep smiling and hope u are satisfied with my answer.Have a good day :)

Answer:

The mean number of the students who develop hypertension over a life time is 7.8.

Step-by-step explanation:

For each person, there are only two possible outcomes, either they will develop hypertension, or they will not. The probability of a person developing hypertension is independent of any other person, which means that the binomial probability distribution is used to solve this question.

Binomial probability distribution

Probability of exactly x successes on n repeated trials, with p probability.

The expected value of the binomial distribution is:

[tex]E(X) = np[/tex]

Suppose that the probability that a person will develop hypertension over a life time is 60%.

This means that [tex]p = 0.6[/tex]

13 graduating students from the same college are selected at random.

This means that [tex]n = 13[/tex]

Find the mean number of the students who develop hypertension over a life time

[tex]E(X) = np = 13*0.6 = 7.8[/tex]

The mean number of the students who develop hypertension over a life time is 7.8.

Answer:

.

Step-by-step explanation:

Answer:

The 95% confidence interval for the population mean is ($6510, $7138).

Step-by-step explanation:

We have the standard deviation for the sample, which means that the t-distribution is used to solve this question.

The first step to solve this problem is finding how many degrees of freedom,which is the sample size subtracted by 1. So

df = 7 - 1 = 6

95% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 6 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.95}{2} = 0.975[/tex]. So we have T = 2.4469.

The margin of error is:

[tex]M = T\frac{s}{\sqrt{n}} = 2.4469\frac{340}{\sqrt{7}} = 314[/tex]

In which s is the standard deviation of the sample and n is the size of the sample.

The lower end of the interval is the sample mean subtracted by M. So it is 6824 - 314 = $6510.

The upper end of the interval is the sample mean added to M. So it is 6824 + 314 = $7138.

The 95% confidence interval for the population mean is ($6510, $7138).

Answer:

graphs 1, 2, 3, and 4, can represent a function

graphs 5 and 6 can not represent a function.

Step-by-step explanation:

If for a given graph of a relationship you can draw a vertical line that intersects the graph in more than one point, then we can conclude that the graph does not represent a function.

Now, if we look at the first four graphs, we can see that no vertical line intersects more than one point, so the first four can represent functions.

The special case here is graph number 2, where we can see a white dot right below a colored dot, and if we draw a vertical line there, the line will touch both points. But, a white dot means that the exact point does not belong to the graph, so if the line passes through there, it will not intersect the graph.

For the last two, this is not the case, in graph 5 and graph 6 we could draw vertical lines that intersect the graphs twice

(any line like x = n, with n < 0, intersects two points in graph 5, while the line x = 0 intersects twice the graph number 6)

So graph 5 and graph 6 can't represent functions.

Answer:

1/120

Step-by-step explanation:

For the first letter, you have a 1/5 chance of getting w

On the second you have a 1/4 chance to get the r

Then 1/3 and 1/2

Next you just multiply the bottom numbers

That gives you how many diffrent outcomes there can be. Put that over 1 and you have your answer.

Hope this helps <3

Answer:

Following are the solution to the given question:

Step-by-step explanation:

The population std. dev of the dog weight=8

[tex]\sigma=8\\\\P(\text{guess with in 16 lbs}) = P(|X-\mu|\leq 16)\\\\=P(-2 \leq Z \leq 2) = 0.9544\\\\[/tex]

Calculating the payout w s.t:

[tex]E[netpay]=0=(-5) \times 0.9544+w\times (1-0.9544)\\\\ w =(5 \times \frac{0.9544}{1-0.9544}) =\$ 104.65[/tex]

therefore, we assume that the weight of the dog is a normal distribution with std. deviation that is 8.

Answer:

true

Step-by-step explanation:

Answer:

C

Step-by-step explanation:

A

[tex]\frac{12}{2\pi }[/tex]  ≈ 1.91 < 2

B

8 - π 8 - 3.14 = 4.86 < 5

C

10π ≈ 31.42 > 30 ← True

D

π + 4 = 3.14 + 4 = 7.14 > 7

Option C is a true inequality

Answer:

x=12,y=3

Step-by-step explanation:

x/6-y/3=1

x can equal 12 because 12/6 is equal to 2.

y can equal 3 because 3/3 equals 1

2-1=1

Answer:

c = 3.00 + .50b

Step-by-step explanation:

The cost is the flat fee plus the cost per book times the number of books

c = 3.00 + .50b

According to my calculations answer is -2

Answer:

4 3/5

Step-by-step explanation:

4/5 - (-3 4/5)

Subtracting a negative is like adding

4/5 + 3 4/5

3 8/5

3 5/5 + 3/5

3+1+3/5

4 3/5

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Answer:

Step-by-step explanation:

The "center-radius" form is ...

  (x -h)² +(y -k)² = r² . . . . . . . circle with center (h, k) and radius r

The graphed circle has its center at (-5, 3) and a radius of 5. Putting these numbers into the above form gives the equation ...

  (x +5)² +(y -3)² = 25 . . . . center-radius form

Expanding the parentheses, we get ...

  x² +10x +25 +y² -6y +9 = 25

Subtracting 25, and putting in general form, the equation becomes ...

  x² +y² +10x -6y +9 = 0 . . . . general form

_____

Additional comment

General form is f(x, y) = 0, where the terms of f(x, y) are lexicographical order and decreasing degree.

Answer:

How to improve my geometry?

Part 1 of 3: Getting the Grade

Attend every class. Class is a time to learn new things and solidify the information that you may have learned in the previous class.

Draw diagrams. Geometry is the math of shapes and angles. ...

Form a study group. ...

Know how to use a protractor. ...

Do all of the assigned homework. ...

Teach the material. ...

Do lots of practice problems. ...

Seek extra help. ...

Step-by-step explanation:

Answer:

18

Step-by-step explanation:

Because angle A and C are equal, it is an isoceles traingle.

This means that side BA is equal to side BC.

Thus, you can set 6x equal to 3x + 9.

Solving that gives you x = 3.

6(3) = 18    3(3) +9 = 18

Answer:

B. 18

Step-by-step explanation:

Since angles A and C are congruent, then sides BA and BC are congruent.

6x = 3x + 9

3x = 9

x = 3

AB = 6x = 6(3) = 18

Answer: B. 18

Answer:

A = 0.46, B = 0.61 and C = 0.46

Step-by-step explanation:

From the number line given, we can see that the distance between 0.5 and the next value is by 0.01, hence to get B, we will add 0.01 to the value of 0.6 as shown;

B = 0.6 + 0.01

B = 0.61

To get A, we will add 0.03 to 0.5 as shown:

A = 0.5 + 0.03

A = 0.53

To get the value of C, we will subtract 0.04 from  0.5

as shown:

C = 0.5 - 0.04

C =0.46

Hence A = 0.46, B = 0.61 and C = 0.46

Answer:

(x-5)^2 + (y+6)^2 = 4

Step-by-step explanation:

The equation of a circle is given by

(x-h)^2 + (y-k)^2 = r^2 where (h,k) is the center and r is the radius

(x-5)^2 + (y- -6)^2 = 2^2

(x-5)^2 + (y+6)^2 = 4

Answer:

The width is:

[tex]-2+\sqrt{26}\text{ meters}\text{ }(\text{or approximately 3.0990 meters})[/tex]

And the length is:

[tex]2+\sqrt{26}\text{ meters}\text{ } (\text{or approximately 7.0990 meters})[/tex]

Step-by-step explanation:

Recall that the area of a rectangle is given by:

[tex]\displaystyle A = w\ell[/tex]

Where w is the width and l is the length.

We are given that the length of a rectangle is four meters longer than the width. Thus:

[tex]\ell = w + 4[/tex]

And we also know that the area of the rectangle is 22 square meteres.

Substitute:

[tex](22)=w(w+4)[/tex]

Distribute and isolate the equation:

[tex]w^2+4w-22=0[/tex]

The equation isn't factorable, so we can instead use the quadratic formula:

[tex]\displaystyle w = \frac{-b\pm\sqrt{b^2-4ac}}{2a}[/tex]

In this case, a = 1, b = 4, and c = -22. Substitute:

[tex]\displaystyle w = \frac{-(4)\pm\sqrt{(4)^2-4(1)(-22)}}{2(1)}[/tex]

Evaluate:

[tex]\displaystyle\begin{aligned} w &= \frac{-4\pm\sqrt{104}}{2}\\ \\ &=\frac{-4\pm\sqrt{4\cdot 26}}{2} \\ \\ &=\frac{-4\pm2\sqrt{26}}{2} \\ \\ & = -2\pm \sqrt{26} \end{aligned}[/tex]

Thus, our two solutions are:

[tex]w_1=-2+\sqrt{26}\approx 3.0990\text{ or } w_2=-2-\sqrt{26}\approx-7.0990[/tex]

Since the width cannot be negative, we can ignore the second solution.

Since the length is four meters longer than the width:

[tex]\ell = (-2+\sqrt{26})+4=2+\sqrt{26}\text{ meters}[/tex]

Thus, the dimensions of the rectangle are:

[tex]\displaystyle (2+\sqrt{26}) \text{ meters by } (-2+\sqrt{26})\text{ meters}[/tex]

Or, approximately 3.0990 by 7.0990.

Answer:

X * 0.8 = $64

x = $80

Step-by-step explanation:

Answer:

$80 (D)

Step-by-step explanation:

If Richard is getting a discount and his final price is $64 that means the answer must be above 64. That eliminates A, B, and C.

Use the formula: 20% of x = $64 and substitute the other two options. 20 percent of 84 is 16.8. 84-16.8=67.2 (not the correct answer). 20 percent of 80 is 16. 80-16=64(The Correct Answer).The answer must be $80 (D)    

Answer:

6.286;

0.0165

0.976

0.1995

Step-by-step explanation:

Given that :

Mean, μ = 243. 4

Standard deviation, σ = 35

Sample size, n = 31

1.)

Standard Error

S. E = σ / √n = 35/√31 = 6.286

2.)

P(x < 230) ;

Z = (x - μ) / S.E

P(Z < (230 - 243.4) / 6.286))

P(Z < - 2.132) = 0.0165

3.)

P(x > 231)

P(Z > (231 - 243.4) / 6.286))

P(Z > - 1.973) = 0.976 (area to the right)

4)

P(x < 248)

P(Z < (248 - 243.4) / 6.286))

P(Z < 0.732) = 0.7679

P(x < 255)

P(Z < (255 - 243.4) / 6.286))

P(Z < 1.845) = 0.9674

0.9674 - 0.7679 = 0.1995

[tex]\sf\huge\underline\color{pink}{༄Answer:}[/tex]

[tex]\tt3 \frac{1}{3} = \frac{x}{6} \\ = \tt \frac{10}{3} = \frac{x}{6} \\ = \tt \frac{x}{6} = \frac{10}{3} \\ = \tt6 \frac{x}{6} = 6( \frac{10}{3} ) \\ = \tt\large\boxed{\tt{\color{pink}{x = 20}}}[/tex]

[tex]\color{pink}{==========================}[/tex]

#CarryOnLearning

9514 1404 393

Answer:

  17.  25 mile per gallon

  18. Eduardo did should have divided by -4.

Step-by-step explanation:

17. The least mileage will be had when the most gas is used to go a given distance. For the given distance, the most gas that could have been used (without adding any) is 18 gallons. Then the least mileage is ...

  (450 mi)/(18 gal) = 25 mi/gal

__

18. The appropriate method for solving this inequality is ...

  -4x/(-4) < 120/(-4) . . . . divide both sides by -4 (and reverse the > symbol)

  x < -30

The step Eduardo took of adding 4 will give ...

  -4x +4 > 124 . . . . . puts him one step farther away from a solution

Eduardo chose an operation to perform that did not get him closer to a solution.

Answer:

2sqrt3

Step-by-step explanation:

Since this seems to be a 45, 45, 90 triangle, x and y are the same.

The hypoteneuse is always the side lengths *sqrt2

We divide the hypoteneuse by sqrt 2 and get sqrt12

sqrt12 simplified is 2sqrt3

Answer:

The figure is not symmetrical

Answered by GAUTHMATH