if A = 1 2 1 1 and B= 0 -1 1 2 then show that (AB)^-1 = B^-1 A^-1


help meeeee plessss ​

Answers

Answer 1

[tex]A = \begin{bmatrix}1&2\\1&1\end{bmatrix} \implies A^{-1} = \dfrac1{\det(A)}\begin{bmatrix}1&-1\\-2&1\end{bmatrix} = \begin{bmatrix}-1&1\\2&-1\end{bmatrix}[/tex]

where det(A) = 1×1 - 2×1 = -1.

[tex]B = \begin{bmatrix}0&-1\\1&2\end{bmatrix} \implies B^{-1} = \dfrac1{\det(B)}\begin{bmatrix}2&1\\-1&0\end{bmatrix} = \begin{bmatrix}2&1\\-1&0\end{bmatrix}[/tex]

where det(B) = 0×2 - (-1)×1 = 1. Then

[tex]B^{-1}A^{-1} = \begin{bmatrix}2&1\\-1&0\end{bmatrix} \begin{bmatrix}-1&1\\2&-1\end{bmatrix} = \begin{bmatrix}-1&3\\1&-2\end{bmatrix}[/tex]

On the other side, we have

[tex]AB = \begin{bmatrix}1&2\\1&1\end{bmatrix} \begin{bmatrix}0&-1\\1&2\end{bmatrix} = \begin{bmatrix}2&3\\1&1\end{bmatrix}[/tex]

and det(AB) = det(A) det(B) = (-1)×1 = -1. So

[tex](AB)^{-1} = \dfrac1{\det(AB)}\begin{bmatrix}1&-3\\-1&2\end{bmatrix} = \begin{bmatrix}-1&3\\1&-2\end{bmatrix}[/tex]

and both matrices are clearly the same.

More generally, we have by definition of inverse,

[tex](AB)(AB)^{-1} = I[/tex]

where [tex]I[/tex] is the identity matrix. Multiply on the left by A ⁻¹ to get

[tex]A^{-1}(AB)(AB)^{-1} = A^{-1}I = A^{-1}[/tex]

Multiplication of matrices is associative, so we can regroup terms as

[tex](A^{-1}A)B(AB)^{-1} = A^{-1} \\\\ B(AB)^{-1} = A^{-1}[/tex]

Now multiply again on the left by B ⁻¹ and do the same thing:

[tex]B^{-1}\left(B(AB)^{-1}\right) = (B^{-1}B)(AB)^{-1} = B^{-1}A^{-1} \\\\ (AB)^{-1} = B^{-1}A^{-1}[/tex]


Related Questions

Two solid spheres have surface areas of 1441 cm? and 2567 cm² respectively. They are melted and recast to form a larger sphere. Find the surface area of the larger sphere in square centimetres.​

Answers

Surface area of small sphere = 1441cm^2

Surface area of bigger sphere = 2567cm^2

Surface area of largest sphere = 1441 + 2567

= 4008cm²

Must click thanks and mark brainliest

3. the third one please answer ASAP write it on paper, please

Answers

The answer is 1/3
To 4/5+3/15-2/3

Answer:

1/3

Step-by-step explanation:

We have to make the denominator of all fractions to be 15:

Multiply both the 4 and the 5 in 4/5 by 3 to get 12/15.

Nothing has to be done to 3/15.

Next, multiply both the -2 and the 3 in -2/3 by 5 to get -10/15.

Solve:

12/15 + 3/15 - 10/15 = 5/15.

5/15 further simplifies to 1/3.

The final answer is 1/3.

A retailer allowed 12% discount and sold a T- shirt at a loss of Rs 16. if he had sold it at 10% discount he would have gained Rs 20.for what price did he purchased the T- shirt.

Answers

Answer:

rs. 100

Step-by-step explanation:

2.5 kg of oranges cost $ 1.40, what is the cost of
1 kg of orange?​

Answers

1 kg of orange costs $0.56

Work:
2.5/1.40 = 1/x

- Cross-multiply
2.5x ÷ 2.5 = x
1.40 ÷ 2.5 = 0.56
x = 0.56

helphelphelphelphelphelp

Answers

Answer:

see image

Step-by-step explanation:

Hi can someone help me with these 3 questions. Thanks :)

Answers

Answer:

a) 45° cause tan = sin/cos and sin 45 and cos 45 both give square root 2/2

b) 120°

c) sin = -1/2 = -30° or 330° both are same

Use the trig circle which i have included in the answer to better understand trig angles

hope that answers your question

I want to let you know that each angle has sets of coordinates the left number is cos and right is sin. Ex) sin of 30 is 1/2 and cos of 30 is square root 3/2 In case you dont fully understand dont hesitate to comment.

good luck!!

Members of a soccer team raised $1946.50 to go to a tournament. They rented a bus for $974.50 and budgeted $60.75 per player for meals. Write and solve an equation which can be used to determine pp, the number of players the team can bring to the tournament.

Answers

Answer:

16 players can be brought to the tournament. The equation is written within my step-by-step explanation.

Step-by-step explanation:

Variable p = number of players

Set up an equation:

974.50 + 60.75p = 1946.50

Isolate variable p:

60.75p = 972

Divide:

p = 16

Check your work:

974.50 + 60.75(16) = 1946.50

974.50 + 972 = 1946.50

1946.50 = 1946.50

Correct!

Answer:

Step-by-step explanation:

21. Andre grew a plant for a science experiment. At the end of his
experiment, the plant was 100.8 centimeters tall. Andre calculated
that the plant grew an average of 3.6 centimeters per day since
the start of his experiment. How many days did Andre's
experiment last?

Answers

Answer:

he answer is 140 minutes to plant 14 saplings.

Step-by-step explanation:

30 divided by 3=10

so it takes 10 minutes to plant one sapling.

10x14=140 so this is how you get your answer. im 99% sure

Answer:

100.8÷3.6=28

he grew the plant for 28 days

Put the following equation of a line into slope-intercept form, simplifying all
fractions.
15x — бу = 48

Answers

Answer:

Step-by-step explanation:

15x-6y=48

-6y=48-15x

y=-8+(15/6)x

y=(5/2)x-8

Please help explanation if possible

Answers

Answer:

y= -2x +8

Step-by-step explanation:

perpendicular lines have a negative reciprocal gradient so

1/2 becomes -2/1 which is the gradient

sub in the values of x and y

2= -2 (3) +C

2= -6 + C

8=C

y=-2x +8

Answer:

y = -2x + 8

Step-by-step explanation:

for me the easiest way is simply to transform the slope and then just determine the y-intersect.

the slope of the original line is 1/2.

it is always the factor of x and represents the y/x ratio of the function (how many units is y changing when x changes a certain number of units).

a perpendicular line (90 degree angle) simply reverses x and y and the sign of the original slope.

so, the slope of the perpendicular line is -2, and the equation is

y = -2x + c

and c we get by using the point coordinates :

2 = -2×3 + c

2 = -6 + c

c = 8

so, we have

y = -2x + 8

how many solutions in 3(6x-2) = 2(9x-3)

Answers

Answer:

Infinite solutions

Step-by-step explanation:

Distribute the numbers

3(6x-2) = 18x - 6

2(9x-3) = 18x - 6

18x - 6 = 18 - 6

Since both sides of the equal sign are the same, that means you can plug any number into x, and it will always be a valid answer.

a giraffe can run 32 miles per hour. what is this speed in feet per second?

Answers

Answer:

46.9 ft/sec

Step-by-step explanation:

A giraffe can run 32 miles per hour. What is this speed in feet per second? Round your answer to the nearset tenth.

5^-4 over 5^3
simplify
A. 5^7
B. 5^-1
C. 1/5
D. 1/5^7​

Answers

Answer:

D is the correct answer.

For each pair of equations, write the letter of the equation that expresses an equal value.
1. a. L = 1 dm3 b. 1 L = 1 cm3
2. a. 1 mL = 1 cm3 b. 1 cm3 = 1 L
3. a. 0°C = –273 K b. 0 K = −273°C
4. a. 1 kg = 100 g b. 1,000 g = 1 kg
5. a. 400 cm = 4.0 m b. 400 cm = 0.40 m
6. a. 1 dm = 10 m b. 1 dm = 0.10 m
7. a. 100°C = 373 K b. 373 K = 10°C

Answers

We must understand that certain standards has been layed down for the conversions of measuring units. A summary of such standards are discussed below:

1. Option A. 1 L = 1 dm³

2. Option A. 1 mL = 1 cm³

3. Option B. 0 K = −273 °C

4. Option B. 1000 g = 1 kg

5. Option A. 400 cm = 4.0 m

6. Option B. 1 dm = 0.10 m

7. Option A. 100°C = 373 K

1. Option A. 1 L = 1 dm³

Option B. 1 L = 1 cm³

From standard measurement,

1 L = 1 dm³

1 L = 1000 cm³

From the measuring standard, we can see that 1 L  ≠ 1 cm³.

Hence, option A gives the correct answer.

2. Option A. 1 mL = 1 cm³

Option B. 1 cm³ = 1 L

Hence, option A gives the correct answer.

From standard measurement,

1 mL = 1 cm³

1000 cm³ = 1 L

Thus, option A gives the correct answer.

3. Option A. 0°C = –273 K

Option B. 0 K = −273 °C

Recall:

T (K) = T(°C) + 273

T (K) = Temperature in Kelvin

T(°C) = Temperature in decree celcius

Next, we shall convert 0°C to K

T(°C) = 0°C

T (K) = T(°C) + 273

T (K) = 0 + 273

T (K) = 273 K

Thus, 0°C is equivalent to 273 K

Next, we shall convert 0 K to °C

T(K) = 0

T (K) = T(°C) + 273

0 = T(°C) + 273

Collect like terms

0 – 273 = T(°C)

T(°C) = –273°C

Thus, 0 K is equivalent to –273°C

Therefore, option B gives the correct answer.

4. Option A. 1 kg = 100 g

Option B. 1000 g = 1 kg

From standard measurement,

1 Kg = 1000 g

1000 g = 1 Kg

Hence, Option B gives the right answer

5. Option A. 400 cm = 4.0 m

Option B. 400 cm = 0.40 m

From standard measurement,

100 cm = 1 m

Converting 400 cm to m, we have:

[tex]400 cm = 1 m\\400 cm = \frac{400 cm * 1 m }{100 cm}\\400 cm = 4 m[/tex]

Thus, option A gives the correct answer.

6. Option A. 1 dm = 10 m

Option B. 1 dm = 0.10 m

From standard measurement,

10 dm = 1 m

Thus,

[tex]1 dm = \frac{1 dm * 1 m}{10 dm}\\1 dm = 0.1 m[/tex]

Therefore, option B gives the correct answer.

7. Option A. 100°C = 373 K

Option B. 373 K = 10°C

Recall:

T (K) = T(°C) + 273

T (K) = Temperature in Kelvin

T(°C) = Temperature in decree celcius

Next, we shall convert 100°C to K

T(°C) = 100°C

T (K) = T(°C) + 273

T (K) = 100 + 273

T (K) = 373 K

Thus, 100°C is equivalent to 373 K

Next, we shall convert 373 K to °C

T(K) = 373

T (K) = T(°C) + 273

373 = T(°C) + 273

Collect like terms

373 – 273 = T(°C)

T(°C) = 100°C

Thus, 373 K is equivalent to 100°C

Therefore, option A gives the correct answer.

SUMMARY:

1. Option A. 1 L = 1 dm³

2. Option A. 1 mL = 1 cm³

3. Option B. 0 K = −273 °C

4. Option B. 1000 g = 1 kg

5. Option A. 400 cm = 4.0 m

6. Option B. 1 dm = 0.10 m

7. Option A. 100°C = 373 K

Learn more:

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Find the nth term of the arithmetic
sequence - 1,2,5, ....

A. 3n - 2
B. -2n + 1
C. 2n + 2
D. 3n - 4

Answers

Answer:

3n -4

Step-by-step explanation:

We are adding 3 each time

-1+3 =2

2+3 = 5

The formula for an arithmetic sequence is

an = a1+d(n-1) where a1 is the first term and d is the common difference

an = -1+3(n-1)

    = -1 +3n -3

    = 3n -4

HELP!!! I will give brainliest, 25 points!!

Mu Alpha Theta, a math honorary club, wants to raise money. The club plans to sell cards and bouquets of flowers for Valentine's Day. Cards cost the club $2 each; bouquets cost the club $3.50 each. Mu Alpha will sell the cards for $6 each, and the flowers for $8 each. The club can spend $360 to buy the cards and the flowers. It wants to collect $900 from its sales. Which linear equation represents this scenario?

A. 2x + 3.5y =360; 6x -8y =900
B. 2x + 3.5y = 360; 8x + 6y = 900
C. 2x - 3.5y = 360; 6x + 8y = 900
D. 2x + 3.5y = 360; 6x + 8y = 900
E. 2x + 6y = 360; 3.5x + 8y = 900
F. No equation.

Answers

Answer:

900

Step-by-step explanation:

2x+3.5y=360 and 6x+8y=900 are two linear equation that represents the given scenario.

We need to find the linear equations for the given situation.

What is the simultaneous equation?

Equations involving two or more unknowns that are to have the same values in each equation.

Let the number of cards be x and the number of flowers be y.

Cards cost the club $2 each; bouquets cost the club $3.50 each. The club can spend $360 to buy the cards and the flowers.

Now, 2x+3.5y=360

Mu Alpha will sell the cards for $6 each, and the flowers for $8 each. It wants to collect $900 from its sales.

Now, 6x+8y=900

Therefore, 2x+3.5y=360 and 6x+8y=900 are two linear equation that represents the given scenario.

To learn more about linear equations visit:

https://brainly.com/question/11897796.

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HELP PLS PLS PLS PLS

now that I have your attention help me answer this question:

Team A built 8 sandcastles in 2 hours and Team B built 5 sandcastles in 1 hour. Which team worked at a faster rate?​

Answers

if you convert it all into one hour, Team B clearly worked at a faster pace.

Answer:

[tex]team \: a \: \\ 8in \: number \: with \: in \: 2 \: hours \\ so \: in \: 1 \: hour \: \frac{8}{2} = 4 \: in \: number \\ \\ team \: b \\ 5 \: in \: 1hour \\ so \: \: team \: b \: work \: in \: fast \\ thank \: you[/tex]

13. What is x in the diagram?

Answers

Answer:

x = 6[tex]\sqrt{3}[/tex]

Step-by-step explanation:

Using the Altitude- on- Hypotenuse theorem

( leg of large triangle)² = (part of hypotenuse below it) × (whole hypotenuse) , so

x² = 9 × (9 + 3) = 9 × 12 = 108 ( take square root of both sides )

x = [tex]\sqrt{108}[/tex] = [tex]\sqrt{36(3)}[/tex] = [tex]\sqrt{36}[/tex] × [tex]\sqrt{3}[/tex] = 6[tex]\sqrt{3}[/tex]

Help me pleaseeeeeeee

Answers

Answer:

The surface area is:

276cm^2

Step-by-step explanation:

10x5=50x2=100

4x5=20x2=40

10x4=40x2=80

100+40+80=220

6x2=12x4=48

2x2=4x2=8

48+8=56

220+56=276

trigonometric identities

Answers

With 180° < θ < 270°, we know that both cos(θ) < 0 and sin(θ) < 0.

Then from the Pythagorean identity, it follows that

sin²(θ) + cos²(θ) = 1   ==>   sin(θ) = -√(1 - cos²(θ))

and so

sin(θ) = -√(1 - (-8/13)²) = -√105/13

Recall the double angle identity for sine:

sin(2θ) = 2 sin(θ) cos(θ) = 2 (-√105/13) (-8/13) = 16√105/169

Find the lateral surface area of the
following prism:
5 cm
5 cm
-apothem = 3.44 cm
5 cm
5 cm
10 cm
5 cm

Answers

Answer:

250 cm²

Step-by-step explanation:

Lateral area of the prism is,

5×10×5

= 250 cm²

Lateral surface area of the given prism is equals to [tex]250cm^{2}[/tex].

What is lateral surface area?

" Lateral surface area is defined as the sum of  area of the all the surfaces except top and bottom of the given geometrical shape."

Formula used

Lateral surface area of pentagonal prism [tex]=5ah[/tex]

[tex]a=[/tex] edge length of the base

[tex]h=[/tex] height of the prism

According to the question,

For the given pentagonal prism,

Edge length of the base [tex]'a' = 5cm[/tex]

Height of the prism [tex]'h' = 10cm[/tex]

Substitute the value in the formula of lateral surface area we get,

Lateral surface area of pentagonal prism [tex]= 5 \times 5\times 10[/tex]

                                                                      [tex]= 250cm^{2}[/tex]

Hence, lateral surface area of the given prism is equals to [tex]250cm^{2}[/tex].

Learn more about  lateral surface area here

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Please Help

The students in a high school are being randomly split into focus and accountability groups that meet each morning for the first fifteen minutes of the school day. Each group contains four students, selected regardless of gender or grade level.

In order to explore the composition of the groups with regard to grade level, you have decided to conduct a simulation using colored discs. Since the number of students in each grade level is about the same, you put the same number of four different colored discs in a bag: red, blue, green, and yellow. You decide that red (r) represents the freshmen, blue (b) represents the sophomores, green (g) represents the juniors, and yellow (y) represents the seniors.

Next, you randomly select one disc from the bag, record the color, and put the disc bag in the bag. You do the same thing three more times to represent one group. Then, you complete this entire process twenty-five times, as shown below.

Based on the results of the simulation, the chances of a group having at least one senior is:


likely

unlikely

neither unlikely or likely

Answers

19/25 which is likely

count the ones with y and put that over 25

Find the value of w in the equation 3w + 15 = 60? Show
your work
. Based on your value of w, what is the value of the expression
below?
8w2 + 8w + 9
PLZ HELPPPP you’ll get all of my points ❤️

Answers

W=15

8(15)2+8(15)+9=369

Answer:

Part 1: Find w

w=15

Step-by-step explanation:

Part 1: Find w

Step 1:

3w+15=60. If this is true, then first: Subtract 15 from both sides.

Result: 3w=45

Step 2:

3w=45. If this is true, now: Divide by 3 to both sides.

Result/Answer: w=15.

Answer:

Part 2: If w=15, then what is 8w2+8w+9?

8w2+8w+9= Well I have 2 options. If you mean 8w^2+8w+9, then the answer is 14529. If you mean 16w+8w+9, then the answer is 369.

the ratio of 62 miles to 100 kilometers

Answers

9514 1404 393

Answer:

  0.99779328

Step-by-step explanation:

The exact conversion factor is ...

  1 mi = 1.609344

Then 62 miles is 62×1.609344 km = 99.779328 km.

The ratio of this to 100 km is ...

  99.779328/100 = 0.99779328 . . . . ratio of 62 miles to 100 km

Please help!!! 25 points!!
-72 + (-30) + 10 =

Answers

-72-30+10.

-72-30=-102

10-102 is also the same as

-102+10

The final answer is -92

Answer:

-92

Step-by-step explanation:

-72 + (-30) + 10 =

-72+ -30

Since they both have the same sign, add and then take the sign

72+30 = 102  and then take the negative sign

-102

-102+10

They have opposite signs, so we subtract and take the sign of the larger

102 -10 = 92

And 102 was negative so take the negative sign

-92

Triangle QRP is congruent to triangle YXZ. What is the perimeter of triangle YXZ?
What is the perimeter of triangle YXZ?

Answers

Answer:

Perimeter of XYZ = Perimeter of QRP

Step-by-step explanation:

Since congruent then

P of XYZ = P of QRP

If m={prime integers between 1 and 11}
N={Factor of 12} find
1. MuN
2.MnN​

Answers

M = {2, 3, 5, 7} (and possibly includes 11 if "between x and y" means to include both x and y)

N = {1, 2, 3, 4, 6, 12}

Then

M U N = {1, 2, 3, 4, 5, 6, 7, 12}

(or possibly {1, 2, 3, 4, 5, 6, 7, 11, 12})

M ∩ N = {2, 3}

a crate of medicine with a density of 167 pounds per cubic foot will ne shipped from the u.s to israel. what is the crates density in kilometers per cubic meter?

Answers

9514 1404 393

Answer:

  2675.08 kg/m³

Step-by-step explanation:

  [tex]\dfrac{167\text{ lb}}{\text{ft}^3}\times\dfrac{0.45359237\text{ kg}}{1\text{ lb}}\times\left(\dfrac{1\text{ ft}}{0.3048\text{ m}}\right)^3\approx\boxed{2675.08\text{ kg/m$^3$}}[/tex]

The diameter of the Moon is 3.5 × 10^3 km.
The diameter of the Sun is 1.4×10^6 km.

Calculate the ratio of the diameter of the Moon to the diameter of the Sun.
Give your answer in the form 1 : n

Answers

Answer:

1 : 400

Step-by-step explanation:

[tex]\frac{3.5 x 10^{3} }{3.5 x 10^{3} } : \frac{1.4 x 10^{6 } }{3.5 x 10^{3} }[/tex]

1 : .4 x [tex]10^{3}[/tex]

1 : 4 x [tex]10^{2}[/tex]

1 : 400

what is the slope in the linear equation y = 2x=1?

Answers

Answer:

The slope of the line is 2

Step-by-step explanation:

y=2x+1, compare it to the slope intercept form of a line, y=mx+c, the slope will be 2

Answer:

its 2

comment for more understanding

Good luck

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