Given:
The matrix is:
[tex]A=\begin{bmatrix}\cos x&-\sin x\\\sin x&\cos x\end{bmatrix}[/tex]
To show:
[tex](A^{-1})^{-1}=A[/tex]
Solution:
If a matrix is:
[tex]M=\begin{bmatrix}a&b\\c&d\end{bmatrix}[/tex]
Then,
[tex]M^{-1}=\dfrac{1}{ad-bc}\begin{bmatrix}d&-b\\-c&a\end{bmatrix}[/tex]
We have,
[tex]A=\begin{bmatrix}\cos x&-\sin x\\\sin x&\cos x\end{bmatrix}[/tex]
Using the above formula, we get
[tex]A^{-1}=\dfrac{1}{(\cos x)(\cos x)-(-\sin x)(\sin x)}\begin{bmatrix}\cos x&\sin x\\-\sin x&\cos x\end{bmatrix}[/tex]
[tex]A^{-1}=\dfrac{1}{\cos^2x+\sin^2x}\begin{bmatrix}\cos x&\sin x\\-\sin x&\cos x\end{bmatrix}[/tex]
[tex]A^{-1}=\dfrac{1}{1}\begin{bmatrix}\cos x&\sin x\\-\sin x&\cos x\end{bmatrix}[/tex]
[tex]A^{-1}=\begin{bmatrix}\cos x&\sin x\\-\sin x&\cos x\end{bmatrix}[/tex]
Now, the inverse of [tex]A^{-1}[/tex] is:
[tex](A^{-1})^{-1}=\dfrac{1}{(\cos x)(\cos x)-(\sin x)(-\sin x)}\begin{bmatrix}\cos x&-\sin x\\\sin x&\cos x\end{bmatrix}[/tex]
[tex](A^{-1})^{-1}=\dfrac{1}{\cos^2x+\sin^2x}\begin{bmatrix}\cos x&-\sin x\\\sin x&\cos x\end{bmatrix}[/tex]
[tex](A^{-1})^{-1}=\dfrac{1}{1}A[/tex]
[tex](A^{-1})^{-1}=A[/tex]
Hence proved.
How do I write
(28/4) - (x+7) in written form?
Answer: The quotient of 28 and 4 minus the sum of a number and 7
Step-by-step explanation:
Please help! will mark right answer with Brianly
Answer:
a. [tex]\frac{4\pi }{3}[/tex]
b. 240
Step-by-step explanation:
all you have to do to find a coterminal angle is to add or subtract 360 or [tex]2\pi[/tex] from the angle, so:
a. [tex]\frac{10\pi }{3} -2\pi =\frac{4\pi }{3}[/tex]
b. -120 + 360 = 240
verify that a÷(b+c)#(a÷b)+(a÷c) for each of the following values of a=6,b=5 and c=7
Answer:
[tex]a \div (b + c) = (a \div b) + (a \div c) \\ 6 \div (5 + 7) = (6 \div 5) + (6 \div 7) \\ 0.5 = 1.2 + 0.86 \\ 0.5 = 2.06[/tex]
he sum of the first two terms of a G.P is 27 whereas the sum of the second and third term is 54. Find the first term and the common ratio.
Answer:
[tex]{ \tt{sum = \frac{a(r {}^{n - 1} )}{n - 1} }} \\ 27 = \frac{a(r {}^{2 - 1} )}{2 - 1} \\ { \bf{27 = ar - - - (i)}} \\ \\ 54 = \frac{a( {r}^{3 - 1} )}{3 - 1} \\ { \bf{108 = a {r}^{2} - - - (ii) }} \\ { \tt{(ii) \div (i) : }} \\ r = \frac{108}{27} \\ { \bf{common \: ratio = 4}} \\ { \bf{first \: term = \frac{27}{4} }}[/tex]
Two spheres have are such that the radius of the bigger sphere is 3 times bigger than the smaller. What is the ratio of the area?
Answer:
1 : 27
Step-by-step explanation:
Radius of sphere one = r₁ = x units
Radius of sphere 2 = r₂ = 3*x = 3x units
Ratio of area of two sphere's = r₁³ : r₂³
= x³ : (3x)³
[tex]= \frac{x^{3}}{3^{3}*x^{3}}\\\\= \frac{1}{3^{3}}\\\\= \frac{1}{27}[/tex]
= 1 : 27
Write an inequality representing the total cost of your purchase. a. Each pound of fruit costs $4. Write an expression that shows the total cost of the fruit. Use the variable you identified in question 1.
Answer:
$4n
Step-by-step explanation:
The variable identified in question 1 isn't given ;
If the cost per unit of fruit = $4
The total cost of fruit will be :
Cost per fruit * number of fruits
If the number of fruits is denoted by the variable, n
The the total cost of fruit will be :
Cost per fruit, $4 * number of fruits, n
Total cost = $4 * n = $4n
When 7 times a number is decreased by 8, the answer is the same as when 3 times the number is increased by 4. Find the number.
Answer:
x=3
Step-by-step explanation:
Equation: 7x-8=3x+4
4x=12
x=3
What is the equation of the following line written in general form?
Answer:
The first option
Step-by-step explanation:
[tex]4x + 5y - 34 = 0[/tex]
Help me to do this question plz plz plz
Answer:
area of parallelogram=base *height
Answer:
area =36cm²
Step-by-step explanation:
area of parallelogram= b×h
9×436cm²hope it helps stay safe healthy and happy..Completing the Square
Guided Practice
Solve the equation by completing the square. If necessary, round to the nearest hundredth.
2x2 - 10x - 20 = 8
A. 27 - 27
B. 7
C.7, -2
Answer:
C.7, -2
Step-by-step explanation:
A quadratic equation is a polynomial of degree two. A quadratic equation is in the form:
ax² + bx + c = 0; where a, b, c are constants.
Quadratic equation can be solved using different methods, such as completing the square method, quadratic formula.
Solving the equation 2x² - 10x - 20 = 8 using completing the square:
2x² - 10x - 20 = 8
2x² - 10x = 28
Divide through by 2, to make the coefficient of x² to be 1:
x² - 5x = 14
Add to both sides, the square of half of the coefficient of x [i.e. (-5/2)² = 6.25]
x² - 5x + 6.25 = 14 + 6.25
(x - 2.5)² = 20.25
taking square root of both sides:
x - 2.5 = √20.25
x - 2.5 = ±4.5
x = 2.5 ± 4.5
x = 2.5 + 4.5; or x = 2.5 - 4.5
x = 7 or x = -2
A box contains 3 red balls, 5 white balls, and 10 green balls. If a ball is chosen at random, what is the probability that it is either white OR green?
a. 3/10
b. 5/6
c. 1/2
d. 1/15
The correct answer is option B which is the probability of either white or green is 5/6.
What is probability?Probability is defined as the ratio of the number of favorable outcomes to the total number of outcomes in other words the probability is the number that shows the happening of the event.
Given that:-
A box contains 3 red balls, 5 white balls, and 10 green balls. If a ball is chosen at random.The probability that it is either white or green will be calculated as:-
Total balls are :- 3+5+10=18
White or green ball - 5+10=15
3 x 5=15
3 x 6=18
P = N(e)/N(s) = 15/18
P = N(e)/N(s) = 5 / 6
Therefore the correct answer is option B which is the probability of either white or green is 5/6.
To know more about probability follow
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A furnace operates at 2,300°F. Before it
can be used to extract metal from an ore,
the temperature must be raised to
3,600°F. This takes place at a rate of
250°F per quarter hour. Which equation
gives the furnace temperature T after q
quarter hours?
A T= 2509 + 2300
B T = 250q + 3600
C T = 2300q + 250
DT= 3600q + 250
Multiply the rate per quarter hour by quarter hours: 250g. This then gets added to the starting temperature of 2300
The answer would be : A. T = 250g + 2300
Is it possible for an angle in a triangle to be opposite both the longest side of the triangle and the shortest side of the triangle? Explain.
Answer: No, it's not possible.
Explanation: An angle must only be opposite exactly one side.
Can someone please help with 5x-4<10
Answer:
Step-by-step explanation:
5x-4<10
or, 5x<14
or, x<14/5
so, x<2.8
[tex]\displaystyle\bf 5x-4<10\\\\5x<14\\\\\boxed{x<2,8} \\\\Answer: x<2,8\quad or \quad x\in(-\infty;2,8)[/tex]
Rewrite 1/5 barrel and 1/2 as a Unit rate
if f(x)=2x/x-5 find f^-1(x)
Answer:
[tex]f^{-1}[/tex] (x) = [tex]\frac{5x}{x-2}[/tex]
Step-by-step explanation:
let y = f(x) and rearrange making x the subject
y = [tex]\frac{2x}{x-5}[/tex] ( multiply both sides by x - 5 )
y(x - 5) = 2x ← distribute left side
xy - 5y = 2x ( subtract 2x from both sides )
xy - 2x - 5y = 0 ( add 5y to both sides )
xy - 2x = 5y ← factor out x from each term on the left side )
x(y - 2) - 5y ← divide both sides by y - 2
x = [tex]\frac{5y}{y-2}[/tex]
Change y back into terms of x with x = [tex]f^{-1}[/tex] (x) , then
[tex]f^{-1}[/tex] (x) = [tex]\frac{5x}{x-2}[/tex]
Look into the image. I hope it helps❤
#CarryOnLearninglet f(x)=7x-4
what is f(6)?
Answer:
38
Step-by-step explanation:
To find the value of f(6), we substitute the value 6 where x is into the function. You would get:
7(6) - 4
42 - 4
f(6) = 38
Answer:
See my writting here have answer
Pls answer 13 b ill mark u brainlist
Answer:
7 students
Step-by-step explanation:
1+2+4=7students
The point-slope form of the equation of a line that passes through points (8, 4) and (0, 2) is y - 4 = - (x - 8). What is
the slope-intercept form of the equation for this line?
O y=1/4x - 12
O y= 1/4x-4
O y= 1/4x +2
O y=1/4x+6
The graph shows a proportional relationship. Which equation matches the
graph?
10
14
12
10
8
6
4
2
10
2
14
4
8
10 12
O A. y = x
O B. y = 2
O C. y = 50
O D. 9=152
Answer:
C.
Step-by-step explanation:
i guess it's letter c. y=50
what is the commen diffrence for this geometric sequnce 4,24,144,864
Answer:
your answer is in the attachment... hope this helps you.!!!!resolver:
[5+(-3+6)+(-2)]-[(-4+10)+(-3)-(-5)]
Which number line model represents the expression 5/2 + 3
The line graph (A) represents the expression 5/2 + 3 the first term is 2 and-a-half units, and the second term is 3 units option (A) is correct.
What is a number line?It is defined as the representation of the numbers on a straight line that goes infinitely on both sides.
We have an expression:
= 5/2 + 3
Here 5/2 = 2.5 = 2 and half
= 2.5 + 3
The first arrow should indicate the 2 and-a-half unit
And the second arrow should represent the 3 unit
The line graph(A) represents the above situation or expression.
Thus, the line graph (A) represents the expression 5/2 + 3 the first term is 2 and-a-half units, and the second term is 3 units option (A) is correct.
Learn more about the number line here:
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Find p(5) for p(x) = 80x2 - 15 by using the remainder theorem.
O 1985
O 2015
O-1985
O 2030
Rule 1: Multiply by 2 then add 1 starting from 1.
Rule 2: Divide by 2 then add 4 starting from 40.
Sequence 1
Sequence 2
Ordered Pairs
PLZ ANSWER FOR Brainiest
Answer:
1×2+1=3
3×2+1=7
7×2+1=15
15x2+1=31
31×2+1=63
40÷2+4=24
24÷2+4÷16
16÷2+4=12
12÷2+4=10
10÷2+4=9
please help me with my work
When you are multiplying by a fraction, you have to flip the sign around and the fraction around. Fiona thought she was dividing in half but in reality, she should be multiplying by 2. 1/2 flipped around is 2/1 which equals 2. And since you switch the division sign to a multiplication sign, the new equation will be 48x2. Which equals 96
Hope this helps and if it does, don't be afraid to give my answer a "Thanks" and maybe a Brainliest if it's correct?
Please helped timed question. Solve for a, b, and A. Round to the nearest tenth.
Answer:
[tex]\angle A=90-72[/tex]
[tex]\angle A=18[/tex]
---------------
[tex]sin~72=\frac{b}{11}[/tex]
[tex]11\times sin~72=6[/tex]
[tex]b=10.5[/tex]
----------------
[tex]11\times cos~72=a[/tex]
[tex]a=3.4[/tex]
----------------
ANSWER:
a=3.4
b=10.5
∠A=18
-----------------------
hope it helps...
have a great day!!
Type the correct answer in the box. Simplify this expression: -2x + 3 – (5 – 6x).
Answer:
4x - 2
Step-by-step explanation:
Given
- 2x + 3 - (5 - 6x) ← distribute parenthesis by - 1
= - 2x + 3 - 5 + 6x ← collect like terms
= 4x - 2
The expression -2x + 3 – (5 – 6x) simplifies to 4x - 2.
What is the correct way of simplifying an expression ?The correct way of simplifying expressions is first solving what are inside the brackets.Then solving divisions then multiplications then additions and last subtractions.This way of solving order has a short name which is BODMAS order.
According to the given question we have to simplify the expression
-2x + 3 – (5 – 6x).
First we'll solve what are inside the brackets.
-2x + 3 - 5 + 6x. (negative sign distributed to get a positive).
= 4x - 2.
= 2(2x - 1).
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The surface area of the cube shown
PLS HELP ASAP¡!!!
A P E X MATH
Answer:
Step-by-step explanation:
Is there an image to see?
