Matrix A is said to be involutory if A2 = I. Prove that a square matrix A is both orthogonal and involutory if and only if A is symmetric.

Answer:

To solve for a, you will need to get that variable alone on one side. First you will multiply each side by variable b. This will give you the equation pb = 3a + 4. Next you subtract 4 from each side. This puts it at pb - 4 = 3a. After that you’ll divide both sides by 3 and get a alone. This gives you (pb - 4)/3 = a or, if you switch it around, a = (pb - 4)/3. This is the simplest form when solving for a in this equation.

Answer:

Hello,

All my sentences will be written in mathematical language.

Step-by-step explanation:

[tex]p=\dfrac{3a+4}{b} \\\\p*b=3a+4 \ :\ \forall\ x,y,z\in\mathbb{R},z\neq 0:x=y\Longleftrightarrow\ x*z=y*z\\\\p*b-4=3a \ :\forall\ x,y,z\in\mathbb{R} :x=y\Longleftrightarrow\ x+z=y+z\\\\\dfrac{p*b-4}{3} =a \ :\forall\ x,y,z\in\mathbb{R},z\neq 0:x=y\Longleftrightarrow\ x*z=y*z\\\\a=\dfrac{p*b-4}{3} \ :\forall\ x,y\in\mathbb{R}:x=y\Longleftrightarrow\ y=x[/tex]

hopefully this answer can help you to answer the next question

Answer:

[tex]y+6=-\frac{1}{2} (x-3)[/tex]

Step-by-step explanation:

Since point-slope form is  [tex]y-y1=m(x-x1)[/tex], you have to plug in the values given to you to create the equation. The "y1" is the "y" coordinate given to us, while the x1 is the x coordinate given to us. So, you have to plug in the x and y coordinates, 3 and -6, into the equation. Since two negatives cancel out to be a positive, y--6= y+6. The "m" stands for the slope, so -1/2 is inserted into the equation, giving us  [tex]y+6=-\frac{1}{2} (x-3)[/tex].

Answer: A. The sampling follows a normal distribution.

              B. Between 25.14 and 30.86

              C. About 95% will contain the true mean and about 5% won't

Step-by-step explanation: A. The sampling is normally distributed because:

B. For a 95% confidence interval: α/2 = 0.025

Since n = 210, use z-score = 1.96

To calculate the interval:

mean ± [tex]z.\frac{s}{\sqrt{n} }[/tex]

Replacing for the values given:

28 ± [tex]1.96.\frac{21}{\sqrt{210} }[/tex]

28 ± [tex]1.96*1.45[/tex]

28 ± 2.84

lower limit: 28 - 2.84 = 25.14

upper limit: 28 + 2.84 = 30.86

Confidence Interval is between 25.14 and 30.86.

C. Confidence Interval at a certain percentage is an interval of values that contains the true mean with a percentage of confidence. In the case of number of times per day students text, 95% of the interval will contain the true mean, while 5% will not contain it.

Answer:

[tex]L + \frac{5}{8} = 1[/tex]

Step-by-step explanation:

Given

A cup of coffee

Kelly drank 5/8 of the coffee

Required

Determine how much is left

Start by representing the amount of coffee left with L

Because the amount of coffee Kelly drank is in fraction (5/8), the total cup of coffee will equate to 1;

Hence, the addition equation as requested in the question to represent the scenario is

[tex]L + \frac{5}{8} = 1[/tex]

Answer:

the answer is d i believe.

Answer:

The answer is D I took the test the other person is right!

Step-by-step explanation:

Step-by-step explanation:

[tex]thank \: you[/tex]

Answer:

20x⁵⁰

Step-by-step explanation:

With the equation √400x¹⁰⁰

we need to take the square root away separately

√400 = √20*20 = 20

Then with x¹⁰⁰

√x¹⁰⁰ = √x⁵⁰*x⁵⁰ = x⁵⁰

So √400x¹⁰⁰ = 20x⁵⁰

hope this helps

The value of g + 100 is 150.

Given that,

The average of g and 100 is 75.

And we have to determine the value of g + 100.

So that means

The arithmetic mean of g and 100 is 75.

So, mathematically it should be

[tex]\frac{g + 100}{2} = 75\\\\[/tex]

So, g + 100 = 150

Therefore we can conclude that the value of g + 100 is 150

Learn more about the mean here: brainly.com/question/11230531

Answer:

9-x^2

Step-by-step explanation:

The difference of means subtracting. the first number is 9 and the second is x^2, so you get 9-x^2

Answer:

It's 28 3/4

Step-by-step explanation:

Answer:

Answer is 19.5

Step-by-step explanation:

27-9+(12-5)÷4

27-9+6÷4   [BOD MAS Rule]

27-9+1.5

28.5-9

19.5

Answer:

A large box weighs 18.5 kilograms and a small box weighs 15.5 kilograms

Step-by-step explanation:

Create a system of equations where l is the weight of one large box and s is the weight of one small box.

2l + 12s = 223

5l + 3s = 139

Solve by elimination by multiplying the bottom equation by -4:

2l + 12s = 223

-20l - 12s = -556

Add these together and solve for l:

-18l = -333

l = 18.5

So, a large box weighs 18.5 kilograms. Plug in 18.5 as l into one of the equations, and solve for s:

5l + 3s = 139

5(18.5) + 3s = 139

92.5 + 3s = 139

3s = 46.5

s = 15.5

A large box weighs 18.5 kilograms and a small box weighs 15.5 kilograms.

9514 1404 393

Answer:

Step-by-step explanation:

Two equations for the total weight can be written in general form as ...

  2L +12S -223 = 0

  5L +3S -139 = 0

These can be solved using the "cross multiplication method" by computing three differences:

  d1 = (2)(3) -(5)(12) = 6 -60 = -54

  d2 = (12)(-139) -(3)(-223) = -1668 +669 = -999

  d3 = (-223)(5) -(-139)(2) = -1115 +278 = -837

Then the weighs of the boxes are ...

  1/d1 = L/d2 = S/d3

  L = d2/d1 = -999/-54 = 18.5

  S = d3/d1 = -837/-54 = 15.5

The large box weighs 18.5 kg; the small box weighs 15.5 kg.

_____

Additional comment

If the coefficients are written in two rows of four numbers, with the first repeated at the end, the pattern of differences can be seen to be (ad -cb) for [a, b] in the first row and [c, d] in the second row of a pair of adjacent columns. This method of solution is fully equivalent to solution using Cramer's Rule for a system of equations represented by a matrix equation.

Answer: about 40.54°

Step by step explanation:

7^2 =  5^2 + 10^2  - 2(5)(10)cos(B)

cos(B)  = (7^2 - 5^2 - 10^2) / (-2(5)(10) )

B = cos-1 [ (7^2 - 5^2 - 10^2) / (-2(5)(10) ]  =  cos-1 (.76) = about 40.54°

Answer:

i [tex]\to[/tex] a

    [tex]n = 96040000[/tex]

i [tex]\to[/tex] b

    [tex]n_1 =24010000[/tex]

i [tex]\to[/tex] c

    [tex]n_2 =41602500[/tex]

ii[tex]\to[/tex]a

     [tex]E = 58.16[/tex]

ii[tex]\to[/tex]b

    [tex]291.84 < \mu < 408.16[/tex]\

ii[tex]\to[/tex]c

    There is insufficient evidence to conclude that the analyst is right because the population mean fee by the analyst does not fall within the confidence interval

Step-by-step explanation:

From the question we are told that

     The sample size is [tex]n = 8[/tex]

      The sample mean is  [tex]\= x = \$ 350[/tex]    

      The sample standard deviation is  [tex]\$ 100[/tex]

Considering question i

    i [tex]\to[/tex] a

         At   [tex]E = 0.02[/tex]  

given that the confidence level is 95%  =  0.95

         the level of significance would be  [tex]\alpha =1-0.95 = 0.05[/tex]

The critical value of  [tex]\frac{\alpha }{2}[/tex] from the normal distribution table is  

        [tex]Z_{\frac{ \alpha }{2} } = 1.96[/tex]

So  the sample size is mathematically evaluated as

            [tex]n = [ \frac{Z_{\frac{\alpha }{2} } * \sigma }{E} ]^2[/tex]

=>        [tex]n =[ \frac{ 1.96 * 100}{ 0.02} ]^2[/tex]

=>         [tex]n = 96040000[/tex]

 i [tex]\to[/tex] b

  At  [tex]E_1 = 0.04[/tex]    and  confidence level  = 95%  =>  [tex]\alpha_1 = 0.05[/tex]   =>  [tex]Z_{\frac{\alpha_1 }{2} } = 1.96[/tex]

             [tex]n_1 = [ \frac{Z_{\frac{\alpha_2 }{2} } * \sigma }{E_1} ]^2[/tex]

=>           [tex]n_1 =[ \frac{ 1.96 * 100}{ 0.04} ]^2[/tex]

=>           [tex]n_1 =24010000[/tex]

 i [tex]\to[/tex] c

       At   [tex]E_2 = 0.04[/tex]     confidence level  = 99%  =>    [tex]\alpha_2 = 0.01[/tex]

The critical value of  [tex]\frac{\alpha_2 }{2}[/tex] from the normal distribution table is  

        [tex]Z_{\frac{ \alpha_2 }{2} } = 2.58[/tex]

=>    [tex]n_2 = [ \frac{Z_{\frac{\alpha_2 }{2} } * \sigma }{E_2} ]^2[/tex]

=>    [tex]n_2 =[ \frac{ 2.58 * 100}{ 0.04} ]^2[/tex]

=>    [tex]n_2 =41602500[/tex]

Considering ii

Given that the level of significance is  [tex]\alpha = 0.10[/tex]

Then the critical value  of  [tex]\frac{\alpha }{2}[/tex] from the normal distribution table is  

           [tex]Z_{\frac{\alpha }{2} } = 1.645[/tex]

Generally the margin of error is mathematically represented as

          [tex]E = Z_{\frac{\alpha }{2} } * \frac{\sigma }{\sqrt{n} }[/tex]

substituting values

         [tex]E = 1.645 * \frac{100 }{\sqrt{8} }[/tex]

         [tex]E = 58.16[/tex]

Generally the 90% confidence interval is mathematically evaluated as

         [tex]\= x - E < \mu < \= x + E[/tex]

=>      [tex]350 - 58.16 < \mu < 350 + 58.16[/tex]

=>     [tex]291.84 < \mu < 408.16[/tex]

So the interpretation is that there is 90% confidence that the mean  fee charged to H&R Block customers last year is in the interval .So there is insufficient evidence to conclude that the analyst is right because the population mean fee by the analyst does not fall within the confidence interval.

Answer:

x=3

Step-by-step explanation:

● -3 (-4x+4) = 15 + 3x

Multiply -3 by (-4x+4) first

● (-3) × (-4x) + (-3)×(4) = 15 + 3x

● 12 x - 12 = 15 +3x

Add 12 to both sides

● 12x - 12 + 12 = 15 + 3x +12

● 12 x = 27 + 3x

Substract 3x from both sides

● 12x -3x = 27 + 3x - 3x

● 9x = 27

Dividr both sides by 9

● 9x/9 = 27/9

● x = 3

Answer:

angleABC=isosceles triangle

angleB=(180-50)÷2=65

angle B=angleX(alternative angle)

angleB=65degree

Answer:

b=a/2

c=a/2

b=c

a=2b and a=2c

Answer:

120 ways

..................

Answer:

24

Step-by-step explanation:

4  friends

1st seat: 4 different people could sit here

Now there are 3 friends left

2nd seat: 3 different people could sit here

Now there are 2 friends left

3rd seat: 2 different people could sit here

Now there are 1 friends left

4th seat: 1 different people could sit here

4*3*2*1

24 ways

perimeter of triangle: P = l+w+h

9+12+10= 31in.

area of triangle: A=b×h÷2

21 + 21 = 42in^2

Answer:

It is, indeed, a reduction. But, the scale factor of the dilation should be a fraction instead of a whole number, since the shape has shrunk.

Instead of [tex]\frac{KN}{K'N'}[/tex], it should be [tex]\frac{K'N'}{KN}[/tex]. That would make it (4 - 2) / (8 - 4) = 2 / 4 = 1/2.

Hope this helps!

Answer:

(x + 3i) * (x - 3i) = x^2 + 3xi - 3xi - 9(i^2) = x^2 + 9

Step-by-step explanation:

| - 4 | = 4

Thus :

f ( | - 4 | ) = f ( 4 )

f ( 4 ) = ( 4 )^2 - 2(4) + 4

f ( 4 ) = 16 - 8 + 4

f ( 4 ) = 16 + 4 - 8

f ( 4 ) = 20 - 8

f ( 4 ) = 12

[tex]10[/tex] divisions between $15.59$ and $15.6$ so each division is $\frac{15.60-15.59}{10}=0.001$

A is 5 division from $15.59$, so, A is $15.59+5\times 0.001=15.595$

similarly, C is 4 division behind $15.59$ so it is $15.590-4\times0.001=15.586$

and B is $15.601$

Answer:

Stratified Random sampling.

Step-by-step explanation:

As per the scenario, It is stratified random sampling as it divides students into strata which represent Sophomores, Juniors, and Seniors.

Simple random samples of the given sizes of the proportional to the size of the stratum which is to be taken from every stratum that is to be about 10 percent of students from every class that is selected here.

Hence, according to the given situation, the correct answer is a random stratified sampling.

Answer:

Cube C

Step-by-step explanation:

[tex]{ \sf{because \: it \: is \: identical}}[/tex]

Answer:

√32

Step-by-step explanation:

Answer:

P-value = 0.0455

Step-by-step explanation:

In this question, we are concerned with calculating the P- value in a test.

Mathematically we know that;

P-value = 2 * P(Z > |z|)

Please check attachment for complete solution and by step explanation

Answer:

hi

Step-by-step explanation:

hji

Answer:

3 s'mores

Step-by-step explanation:

If we center our attention on how many marshmallows you need per s'more which is 2 and you only have 7 you can only make 3 with one marshmallow remaining.

Answer:

[tex]x^6 - \frac{7x^5}{5} - 3x^3 + C[/tex]