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:

A. <BED and <DEA, <AEC and <BEC

Step-by-step explanation:

Supplementary angles add up to give 180°.

m<BED = 90°

m<DEA = 90°

m<BED + m<DEA = 180°

Therefore, <BED and <DEA are supplementary.

m<AEC = 90°

m<BEC = 90°

m<AEC + m<BEC = 180°

Therefore, <AEC and <BEC are supplementary.

Answer:

Step-by-step explanation:

The breaking point for the graph (if there was one), is one. That means at one the function you use changes.

It goes from x^2 to 2x + 1

Answer A

Here's the catch. Where is 0? Zero is less than one. So what do you use? The answer is that f(x) = x^2

Answer B

if f(x) = x^2 then wherever you see an x, you put in 0.

f(x) = x^2

f(0) = 0^2

You could multiply 0 by itself a million times and it would still get 0.

f(0) = 0

Answer:

x= 30 degrees

Step-by-step explanation:

This is an isosceles triangle as indicates by the lines on the sides.

Since the sides lengths are equal, the base angles are  equal

x= 30 degrees

Answer:

[tex]2y + 3y + x = 180 \\ 5y + 30 = 180 \\ 5y = 180 - 30 \\ 5y = 150 \\ y = 30[/tex]

QOR =3Y

=3×30

=90°

ROS = 2Y

=2×30

=60°

Answer:

20km/hr

Step-by-step explanation:

Given that a ship sailed 30km in one and a half hours. We need to find out the rate of ship in kilometres/hour . The rate is also called Speed.

Speed:- Distance travelled per unit time is called Speed .

Here , according to Question,

Distance = 30 km

Time = 1½ hrs .

We know that ,

[tex]\rm\implies Distance = Speed \times Time [/tex]

Subsequently ,

[tex]\rm\implies Time = \dfrac{Distance}{Time} [/tex]

Substitute the respective values ,

[tex]\rm\implies Rate =\dfrac{ 30km}{ 1.5 hrs } [/tex]

We can write 1.5 as 3/2 , therefore ,

[tex]\rm\implies Rate = \dfrac{ 2\times 30}{3} km/hr[/tex]

Simplify the RHS ,

[tex]\rm\implies\boxed{\blue{\rm Rate = 20\ km/hr}} [/tex]

Hence the Rate/Speed of the ship is 20km/hr .

Answer:

x-intercept is (-3/7, 0) and the y-intercept is at (0, 3)

Step-by-step explanation:

Given the function y = 7x + 3

The x-intercept occurs at y = 0. Substituting y = 0 into the expression, we will have:

0 = 7x + 3

7x + 3 = 0

7x = -3

x = -3/7

Similarly, the y-intercept occurs at x = 0. Substituting x = 0 into the expression, we will have:

y = 7(0) + 3

y = 0 + 3

y = 3

Hence the x-intercept is (-3/7, 0) and the y-intercept is at (0, 3)

Answer:

We fail to reject the null and conclude thattherw is no difference in population means.

Step-by-step explanation:

Before After

5.6 6.4

1.3 1.5

4.7 4.6

3.8 4.3

2.4 2.1

5.5 6.0

5.1 5.2

4.6 4.5

3.7 4.5

H0 : There is no difference in population

H1 : There population are not all equal

Difference, d = (Before - After)

d = -0.8, -0.2, 0.1, -0.5, 0.3, -0.5, -0.1, 0.1, -0.8

The test statistic :

T = dbar / (Sd/√n)

dbar = Σx / n = - 2.4 / 9 = 0.2666

Standard deviation of difference Sd; [√Σ(d - dbar)² / n-1]

Sd = 0.403 (using calculator)

Hence,

T = dbar / (Sd/√n)

-0.266 / (0.403/√9)

-0.266 / 0.1343333

= - 1.980

The Pvalue ;

df = n - 1 ; 9 - 1 = 8

Pvalue(-1.980, 8) = 0.083

α = 0.05

Since Pvalue > α; We fail to reject the null and conclude thattherw is no difference in population means.

Answer:

36

Step-by-step explanation:

Area of a triangle = (bh)/2

Where b = base length and h = height

Given base length: 18ft

Given height: 4ft

This being known let's define the variables

b = 18

h = 4

Now to find the area we simply plug in these values into the formula

Area = (18)(4)/2

Simplify multiplication 18 * 4 = 72

Area = 72/2

Simplify division

Area = 36

Answer: A) 45 ft

Step-by-step

The yardstick is 3ft tall since 1 yard = 3ft. It is 3 times as tall as its shadow. The tree has a 15ft long shadow. The tree should also be 3 times as tall as its shadow. The tree is 15*3ft tall, so it is 45ft tall. I attached an image of the diagram I made.

Answer:

A.

Step-by-step explanation:

A for apple....

Dwuhhhhhhhhhhhhh

Isss ezeewer dan anytwing

Answer:

Step-by-step explanation:

Set up the following proportion. x is the number of games you should win.

11/18 = x / 162  

11*162 / 18 = x

x = 99            You likely would be out of the playoffs with a number like this.

Answer:

c. 54[tex]\pi[/tex] in.³

The volume of cylinder is 54[tex]\pi[/tex] in.³

Step-by-step explanation:

Given that :-

To Find :-

Solution:-

We use formula

Volume of cylinder = π × (radius)² × h

Volume of cylinder = π × ( 3)² × 6.

Volume of cylinder = π × 9 × 6.

Volume of cylinder = 54[tex]\pi[/tex] in.³

The formula we use,

→ Volume of cylinder = π × r² × h

It is given that,

→ Height (h) = 6 and radius (r) = 3.

Then we have to,

find the volume of the cylinder,

→ π × r² × h

→ π × 3² × 6

→ π × 9 × 6

→ 54π in.³

Thus, option (c) is the answer.

Answer:

C. Method 1 is an observational study because no attempt is made to influence results.

Step-by-step explanation:

Based on the descriptions provided: Method 1 is an observational study because no attempt is made to influence the results. Option 3 is the correct answer.

An observational study is a type of study where researchers observe and collect data without actively intervening or manipulating any variables.

Method 1 involves surveying shoppers and asking them about their detergent use and laundry cleanliness ratings. The researcher is merely collecting data without intervening or manipulating any variables. The study relies on the natural behavior of shoppers and their responses.

Method 2, on the other hand, involves actively creating soiled fabrics and washing them with different detergents. This intervention introduces an element of manipulation, making it more of an experimental study than an observational one.

To know more about observational study :

https://brainly.com/question/29141360

#SPJ3

Answer:

(a) [tex]P(Online\ Training) = 0.750[/tex]

(b) [tex]Pr = 0.169[/tex] --- Quality Division and Online Training

(c) [tex]P(A\ |\ B) = 0.686[/tex] --- Online Training given Sales Division

Step-by-step explanation:

Given

The two-way table

Solving (a): P(Online Training)

The total employee is:

[tex]Total = 136[/tex]

The employees for online training is:

[tex]Online\ Training = 102[/tex]

So, the probability is:

[tex]P(Online\ Training) = \frac{102}{136}[/tex]

[tex]P(Online\ Training) = 0.750[/tex]

Solving (b): P(Quality Division and Online Training)

The number of employees that choose quality Division and online training is 23

So, the probability is:

[tex]Pr = \frac{23}{136}[/tex]

[tex]Pr = 0.169[/tex]

Solving (c): P(Online Training | Sales Division)

This is calculated as:

Let:

[tex]A \to[/tex] Online training

[tex]B \to[/tex] Sales division

So, we have:

[tex]P(A\ |\ B) = \frac{n(A\ n\ B)}{n(B)}[/tex]

From the table:

[tex]n(A\ n\ B) =35[/tex]

[tex]n(B) = 16 + 35 = 51[/tex]

So, the probability is:

[tex]P(A\ |\ B) = \frac{35}{51}[/tex]

[tex]P(A\ |\ B) = 0.686[/tex]

Answer: I got 7120 seconds

Step-by-step explanation:

There's 178 seconds in the song (for more context, I just converted the 2 minutes into seconds and added it with 58) then I multiplied it by the total amount of times it played (in this case, 40)

Hope this helps

Answer:

75% cotton

Step-by-step explanation:

3/4=75%

1/4=25%

total 100%

Answer:

the answer is option A population standard deviation

Answer: x³+y³=180

Step-by-step explain:                                                                                            let's remember the formula                                                                                 x³+y³=(x+y)(x²-xy+y²) and also  x³+y³=(x+y)³-3xy(x+y)                                              then                                                                                      [tex]\displaystyle\boldsymbol{ x^3+y^3=\underbrace{(x+y)^3}_{6}-3\underbrace{xy}_{2}\underbrace{(x+y)}_6}=\\\\6^3-3\cdot 2\cdot 6=216-36=180[/tex]                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                

Answer:

Reject H0 and conclude that population means are different.

Step-by-step explanation:

H0: μ1 = μ2

H1: μ1 ≠ μ2

x1 = 11 ; σ1 = 4 ; n1 = 49

x2 = 14 ; σ2 = 5 ; n2 = 64

The test statistic :

(x1 - x2) / sqrt[(σ1²/n1 + σ2²/n2)]

Test statistic :

(11 - 14) / sqrt[(4²/49 + 5²/64)]

Test statistic :

-3 / √0.7171556

Test statistic = - 3.542

Using α = 0.01

The critical value Zα/2 ; Z0.01/2 = 2.58

Decison region :

Reject H0 : if Test statistic < Zcritical

Reject H0 : - 3.542 < - 2.58

Answer:

Step-by-step explanation:

x = 4y+18

xy = -18

x = -18/y

-18/y = 4y+18

4y² + 18y + 18 = 0

2y² + 9y + 9 = 0

y = [-9 ±√(9²-4(2)(9))]/[2(2)] = [-9 ± 3]/4 = -1.5, -3

-1.5 is an extraneous solution, so y = -3

x = 6

Answer:

[tex]\frac{1}{36} = 0.0278[/tex] = 2.78% probability it will land on both 2 sides.

Step-by-step explanation:

For each trial, there are only two possible outcomes. Either it lands on 2, or it does not. The probability of the spinner landing on two in a trial is independent of any other trial, which means that the binomial probability distribution is used to solve this question.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]

In which [tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.

[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]

And p is the probability of X happening.

One of the six sides is 2:

This means that [tex]p = \frac{1}{6}[/tex]

If the spinner is spun two times, what is the probability it will land on both 2 sides?

This is P(X = 2) when n = 2. So

[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]

[tex]P(X = 2) = C_{2,2}.(\frac{1}{6})^{2}.(\frac{5}{6})^{0} = \frac{1}{36} = 0.0278[/tex]

[tex]\frac{1}{36} = 0.0278[/tex] = 2.78% probability it will land on both 2 sides.

Answer:

nose

Step-by-step explanation:

Answer:

i think its b

Step-by-step explanation:

Answer:

[tex]25\text{ feet}[/tex]

Step-by-step explanation:

The ladder, ground, and building form a right triangle where the vertical distance between the top of the ladder and the bottom of the ground is one leg, the horizontal distance between the bottom of the ladder and the building is another leg, and the length of the ladder is the hypotenuse.

For any right triangle, the Pythagorean Theorem states that the sum of the squares of both legs is equal to the hypotenuse squared ([tex]a^2+b^2=c^2[/tex]), where [tex]c[/tex] is the hypotenuse.

Let the length of the ladder be [tex]\ell[/tex] (hypotenuse of right triangle). The distance between the top of the ladder and the ground (vertical distance) can be represented as [tex]\ell -1[/tex].

From the Pythagorean Theorem, we then have:

[tex]7^2+(\ell-1)^2=\ell^2[/tex]

Expand using [tex](a-b)^2=a^2-2ab+b^2[/tex]:

[tex]49+\ell^2-2\ell+1=\ell^2[/tex]

Subtract [tex]\ell[/tex] from both sides and add [tex]2\ell[/tex] to both sides:

[tex]49+1=2\ell[/tex]

Combine like terms:

[tex]50=2\ell, \\2\ell =50[/tex]

Divide both sides by 2:

[tex]\ell=\frac{50}{2}=\boxed{25\text{ feet}}[/tex]

Therefore, the length of the ladder is 25 feet.