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.
Another of Bhaskara's problems results in a quadratic equation Parthava was enraged and seized a certain number of arrows to slay Karna. He expended one-half of them in defending himself. Four times the square root of the number of arrows were discharged against the horses. With six more, he transfixed Shalya, the charioteer. With three more, he rent the parasol, the standard, and the bow; and with the last one he pierced the head of Karna. How many arrows did Parthava have?
Answer:
Parthava had 100 arrows.
Step-by-step explanation:
Let's define N as the number of arrows that Parthava originally has.
He uses one-half of them in defending himself, so he used N/2 arrows
Now he uses four times the square root of the number of arrows, so now he uses:
4*√N
Then he uses 6
Then he uses 3
Then he uses the last one.
If we add all these numbers of arrows that he used, we should get the initial number of arrows that he used, then:
N/2 + 4*√N + 6 + 3 + 1 = N
Now we have an equation that we can try to solve.
First, let's move all the terms to the same side:
N/2 + 4*√N + 6 + 3 + 1 - N = 0
now we can simpify it:
(N/2 - N) + 4*√N + (6 + 3 + 1) = 0
-(1/2)*N + 4*√N + 10 = 0
Now we can define a new variable x = √N
Then we have: x^2 = N
now we can replace these new variables in our equation to get:
-(1/2)*x^2 + 4*x + 10 = 0
Now we just have a quadratic equation.
Remember that for a quadratic equation of the form:
0 = a*x^2 + b*x + c
The solutions were given by:
[tex]x = \frac{-b \pm \sqrt{b^2 - 4*a*c} }{2a}[/tex]
Then in our case, the solutions will be:
[tex]x = \frac{-4 \pm \sqrt{4^2 - 4*(-1/2)*10} }{2*(-1/2)} = \frac{-4 \pm 6 }{-1} = 4 \pm 6[/tex]
So there are two solutions:
x = 4 + 6 = 10
x = 4 - 6 = -2
And remember that x = √N
Then x should be positive, then we take x = 10 as our solution here.
then we can use the equation:
x = 10 = √N
then
10^2 = √N^2 = N
10^2 = 100 = N
Parthava had 100 arrows.
please help! need answers in order to move on:)
1.) which number equals (5)^-3?
- -125
- 1/15
- 1/125
- -15
2.) find the equivalent for -(3)^-4
- -(4x4x4)
- -3x-4
- 1/-3x-3x-3x-3
- -(1/3x1/3x1/3x1/3)
3.) which of the following is equivalent to 3^-8x3^4
- 3^-12
- 3^-4
- 3^-2
- 3^-32
4.) which value is equivalent to 7^-3/7^-5
- 7^15
- 7^-2
- 7^8
- 7^2
5.) choose the equivalent expression (8^10)^2
- 8^12
- 8^20
- 8^8
- 8^5
6.) which expression is equivalent to (9x8)^4
- 9x8x4
- 9^4x8^4
- (9^8)^4
- (9^4)^8
7.) which expression is equivalent to (2/7)^5
- 2^5/7^5
- 2x5/7x5
- 2^5/7
- 2x5/7
Answer:
1)
5⁻³ = 1/5³ = 1/1252)
-3⁻⁴ = -(1/3)⁴ = -(1/3×1/3×1/3×1/3)3)
3⁻⁸ x 3⁴ = 3⁻⁸⁺⁴ = 3⁻⁴4)
7⁻³/7⁻⁵ = 7⁻³ ⁻⁽⁻⁵⁾ = 7⁻³⁺⁵ = 7²5)
(8¹⁰)² = 8¹⁰*² = 8²⁰6)
(9x8)⁴ = 9⁴x8⁴7)
(2/7)⁵ = 2⁵/7⁵Answer:
1) [tex]5^{-3}[/tex]-
Exponent rule:- [tex]a^{-b}=\frac{1}{a^b}[/tex]
[tex]5^{-3}=\frac{1}{5^3}[/tex]
[tex]=\frac{1}{5^3}[/tex]
[tex]5^3=125[/tex]
Answer:- [tex]\frac{1}{125}[/tex]
---------
2) [tex]-3^{-4}[/tex]
[tex]-(\frac{1}{3} )^{4}[/tex]
Answer:- [tex]-(\frac{1}{3}\times\frac{1}{3} \times \frac{1}{3} \times\frac{1}{3} )[/tex]
---------
3) [tex]3^{-8}\times 3^{4}[/tex]
[tex]3^{-8+4}[/tex]
Answer:- [tex]3^{-4}[/tex]
----------
4) [tex]7^{-3} /7^{-5}[/tex]
[tex]7^{-3-(-5)}[/tex]
[tex]7^{-3+5}[/tex]
Answer:- [tex]7^{2}[/tex]
----------
5) [tex](8^{10} )^{2}[/tex]
[tex]8^{10\times2}[/tex]
Answer:- [tex]8^{20}[/tex]
---------
6) [tex](9\times8)^{4}[/tex]
Answer:- [tex]9^{4} \times 8^{4}[/tex]
---------
7) [tex]\left(\frac{2}{7}\right)^5[/tex]
Answer:- [tex]\frac{2^{5} }{7^{5} }[/tex]
-----------------------
OAmalOHopeO
-----------------------
Which equation relates the population (P) in millions to the time that has passed (T) if the growth rate is 4% per year and the starting
population is 10 million people?
(1) P = 10(0.96)^T
(2) P = 10(1.04)^T
(3) P = 10 + 10(0.04)^T
(4) P = 10(1.4)^T
Answer:
Step-by-step explanation:
The model for exponential growth/decay is
[tex]P(t)=a(b)^t[/tex] where a is the initial population and b is the growth/decay rate. Filling in the info you were given:
[tex]P(t)=10(1.04)^t[/tex]
Because this is a growth rate, we have 100% of the population and that population is growing by 4%, which is .04 in decimal form. If the population is not declining, we are adding to the 100% of the population we already have. That's why the growth rate is 1.04.
.96 means that the population is declining at 4% each year; and 1.4 means that the population is growing at 140% instead of the 104% that it is.
please answer this question!!
Answer:
a
Step-by-step explanation:
all angles of an equilaterall triangle are equal therefore 180÷3 = 60
Help please!
Find the inverse equation of this function
f(x) = (x + 6)^2 + 1
Thank you!!
Step-by-step explanation:
you're just going to switch x and y and then solve for y
Answer:
Hello,
Step-by-step explanation:
The problem is that the inverse function is not a function but
an union of 2 functions.
[tex]y=(x+6)^2+1\ is\ the\ orignal\ function\ f(x).\\\\Inverting\ x\ and\ y\ gives: \ x=(y+6)^2+1\\\\(y+6)^2=x-1 \ nota\ bene\ x-1\geq 0 \\(y+6)^2-(x-1)=0\\\\((y+6)-\sqrt{x-1} ) * ((y+6)+\sqrt{x-1}) =0\\\\y=-6+\sqrt{x-1}-6\ or\ y=-6-\sqrt{x-1}\\[/tex]
For the fun
,[tex]f_1(x)= (x+6)^2+1=0\ if\ x<6\\f_1^{-1}(x)=-6-\sqrt{x-1} =0\ if\ x<6\\\\f_2(x)=(x+6)^2+1=0\ if\ x \geq 6\\\\f_2^{-1}(x)=-6+\sqrt{x-1} =0\ if\ x\geq 6\\[/tex]
Convert 5π∕6 radians to degrees. Question 1 options: A) 25° B) 150° C) 150π° D) 1080°
Step-by-step explanation:
Hi there!
Given;
= 5(π\6)
We have;
π = 180°
Keeping value of π in the question;
= 5(180°/6)
= 5*30°
= 150°
Therefore, answer is option B.
Hope it helps!
The denominator of a fraction exceeds twice the numerator of the fraction by 10. The value of this fraction is 5/12. Find the fraction.
Answer:
25/60
Step-by-step explanation:
Numerator = n
[tex]\frac{n}{2n + 10} = \frac{5}{12}[/tex]
Cross multiply:
n * 12 = (2n + 10) * 5
12n = 10n + 50
12n - 10n = 10n + 50 - 10n
2n = 50
n = 25
Fraction = [tex]\frac{25}{60}[/tex]
If my answer is incorrect, pls correct me!
If you like my answer and explanation, mark me as brainliest!
-Chetan K
Answer:
25/60
Step-by-step explanation:
Study Island:)
Using the following equation, find the center and radius:
x2 + 2x + y2 + 4y = 20
Answer:
centre = (- 1, - 2 ) , radius = 5
Step-by-step explanation:
The equation of a circle in standard form is
(x - h)² + (y - k)² = r²
where (h, k) are the coordinates of the centre and r is the radius
Given
x² + 2x + y² + 4y = 20
To obtain equation in standard form use method of completing the square
add ( half the coefficient of the x/y terms )² to both sides
x² + 2(1)x + 1 + y² + 2(2)y + 4 = 20 + 1 + 4
(x + 1)² + (y + 2)² = 25 = 5² ← in standard form
with centre = (- 1, - 2 ) and r = 5
I need help with this question...
Q: Five days last month it rained 6.5 inches. It rained 3.5 inches in 7 days last month. How many inches did it rain those 12 days?
Answer:
57 inches
Step-by-step explanation:
It rained 5*6.5+7*3.5=32.5+34.5=57 inches in the past 12 days
In which of the following triangles is cos B = 0.8?
A
B
C
D
Answer:
B
Step-by-step explanation:
b is the symbol for the side opposite angle B. c is the symbol for the side opposite Using the notation in the above triangles
The triangle that is cos b = 0.8 is triangle d.
The triangles in the diagram are right triangle. Right triangles are triangles that have an angle that is 90 degrees. The sum of angles is 180 degrees.
In order to make use of cos, the value of the adjacent and the hypotenuse would be needed.
Cos = adjacent / hypotenuse
Triangle A:
The value of the adjacent side would be determined using pythagoras theroem
5² - 4²
= 25 - 16
= √9 = 3
Cos B = 3/5 = 0.6
Triangle B:
Cos B = 5/8 = 0.625
Triangle C:
Value of the hypotenuse = 4² + 5²
16 + 25
√41 = 6.4
Cos B = 4/6.4 = 0.62
Triangle D:
Cos B = 4/5 = 0.8
To learn more about triangles, please check: https://brainly.com/question/7894175
Please help. TIMED! (15 pts)
Use the following data to calculate the curve of the best-fit.
Answer:
y = 0.4x^2 + 3.4x + 4
Step-by-step explanation:
The coordinates (-5,-3) work with this equation. Please give brainliest, I need 1 more to move on to the next tier.
Answer:
2nd option
Step-by-step explanation:
putting x = 1 in the 3rd option,
0.4+3.4+4 = 7.8
Ella bought a 2 bedroom unit 12 years ago for $95 000 and recently sold it for $280 000 (after deducting selling costs).
a) Find the profit.
b) Find the profit as a percentage of the buying price.
c) Find the profit as a percentage of the selling price.
d) Which percentage profit sounds better as far as Ella is concerned?
pls explain, thanks!!!!
C.P. = $95000
S.P. = $280000
a. Profit
= S.P. - C.P.
= $280000 - $95000
= $185000
b. Let the profit% of C.P. be x.
(x/100) × $95000 = $185000
=> x/100 = $185000/$95000
=> x/100 = 37/19
=> x = (37/19) × 100
=> x = 3700/19
=> x = 194 14/19
So, profit percent of buying price is 194 14/19%.
c. Let the profit% of S.P. be x.
(x/100) × $280000 = $185000
=> x/100 = $185000/$280000
=> x/100 = 37/56
=> x = (37/56) × 100
=> x = 3700/56
=> x = 925/14
=> x = 16 1/14
So, profit percent of selling price is 16 1/14%.
d. Buying price percentage profit sounds better as far as Ella is concerned.
1+-2/3--m where m=9/2
Answer:
-25/9
Step-by-step explanation:
1 + (-2/3) - m
Plug in:
1 + (-2/3) - 9/2
1 + 2/3 - 9/2
1/3 - 9/2
-25/9
Hope this helped.
Answer:
4 5/6
Step-by-step explanation:
1+-2/3--m
Subtracting a negative is like adding
1-2/3 +m
1/3+m
m = 9/2
1/3 +9/2
Get a common denominator of 6
1/3 *2/2 +9/2*3/3
2/6 + 27/6
29/6
Changing to a mixed number
4 5/6
Find the missing side of this right
triangle.
Х
7
12
X =
V[?
Answer:
[tex]\sqrt{193}[/tex]
Step-by-step explanation:
[tex]a^{2} +b^{2} =c^{2}[/tex]
a = 7
b = 12
[tex]7^{2} + 12^{2}[/tex] = 193
I hope this helped!! :)have a great day! :)Translate each verbal expression to an algebraic expression.
1. 6 less than the product of a cubed number and 15
2. The sum of the product of 4 and a squared number and the quotient of 5 and 3.
Step-by-step explanation:
Let the number be x, thenx³×15-6
15x³-6
2. Let the number be y, then
(4×y)+(5/3)
4y+5/3
Rob cuts a circular hole out of a rectangular piece of paper. The paper measures 20 centimeters by 30 centimeters. The hole is 10 centimeters in diameter. How much of the piece of paper, in square centimeters, is left over after the hole is cut out?
Answer:
521.25
Step-by-step explanation:
the circle is 78.75 in area and the square is 600 so 600- 78.75 = 521.25
multiple the following
[tex] \frac{18}{15} \times \frac{25}{12} [/tex]
Answer:
5/2
Step-by-step explanation:
(18/15)*(25/12)=(18*25)/(15*12)=450/180=5/2
Someone plssss help me with this question!!
Answer:
There are 3 possible values for a.
Step-by-step explanation:
a/b=2/3
3a=2b
If b>5 and b<13
apply all possible values
b=6 -> 3a=12 ==> a=4 1st possibility
b=7 -> 3a=14 ==> a=4.something Not a possibility
b=8 -> 3a=16 ==> a=5.something Not a possibility
b=9 -> 3a=18 ==> a=6 2nd possibility
b=10 -> 3a=20 ==> a=6.something Not a possibility
b=11 -> 3a=22 ==> a=7.something Not a possibility
b=12 -> 3a=24 ==> a=8 3rd possibility
1a.-14,____,-6,____,2,____,10
b. ____, - 2,4,____,16,____,64
2.Factor of 60=
1,2,3,4,5,6,10,x,15,20,y,z
Find the sum of the values of x, y and z
Please help me to solve these question, thank you.
Answer:
102
Step-by-step explanation:
x= 12
y= 30
z= 60
Hope u got it
Answer:
Hello,
a) -6
b) -39
c) 102
Step-by-step explanation:
I suppose this are sequence arithemical or geometrical
[tex]a)\\u_1=-14\\u_2=x\\u_3=-6\\u_4=y\\u_5=2\\u_6=z\\u_7=10\\\\We\ see\ that\ :\\u_3-u_1=-6-(-14)=-6+14=8\\u_5-u_3=2-(-6)=2+6=8\\u_7-u_5=10-2=8\\\\We\ may \imagine\ that\ the\ difference\ bethween\ 2\ terms\ is\ =8/2=4\\\\so\ x=-10, y=-2, z=6 \ and\ x+y+z=-10+(-2)+6=-6\\[/tex]
[tex]b)\\u_1=x\\u_2=-2\\u_3=4\\u_4=y\\u_5=16\\u_6=z\\u_7=64\\\\We\ see\ that\ :\\\\\dfrac{u_5}{u_3}=\dfrac{16}{4} =4\\\dfrac{u_8}{u_6}=\dfrac{64}{16} =4\\\dfrac{u_3}{u_2}=\dfrac{4}{-2} =-2\\\\The\ common\ factor\ is\ -2\\\\u_1=x=\dfrac{u_2}{-2} =1\\\\u_4=y=\dfrac{u_5}{-2} =-8\\\\u_6=z=\dfrac{u_7}{-2} =-32\\x+y+z=1+(-8)+(-32)=-39\\[/tex]
c)
All those numbers are divisor of 3*4*5=60
x=12, y=30, z=60
x+y+z=12+30+60=102
what’s the scale reading
Answer:
0.026
Step-by-step explanation:
6 out of 10 steps between 0.02 and 0.03.
Determine the measure of the interior angle at vertex E.
A. 135
B. 45
C. 225
D. 75
Answer:
135
Step-by-step explanation:
The sum of the interior angles of a pentagon is 540
3x+3x+2x+2x+2x = 540
12x = 540
Divide by 12
12x/12 = 540/12
x = 45
E = 3x = 3*45 = 135
Answer:
135
Step-by-step explanation:
Which inequality is represented by this graph?
Answer:
x> 0
Step-by-step explanation:
There is an open circle at 0 so this means it is not equal to
The line goes to the right so x is greater than
x> 0
Will give brainliest to the first person
Step-by-step explanation:
Area=b×h
= (x+5)×(x+6)
=x^2+6x+5x+30
=x^2+11x+30
If u simplify u will get (x+5)(x+6) as answer.
Keep smiling and hope u are satisfied with my answer.Have a good day :)
Lorraine writes the equation shown. x²+4-15=0 She wants to describe the equation using the term relation and the term function. The equation represents a relation and a function a relation but not a function a function but not a relation neither a relation nor a function
Answer:
Neither a relation nor a function
Step-by-step explanation:
A relation in mathematics is a relationship between two or more set of values in an ordered pair, such as related x and y-values
An equation is a statement that gives declare the equality between two expressions
A function is a mapping rule that maps each element in the domain set to only one element in the range set
Therefore, the given equation in one variable, x, that asserts the equality of the expressions on the left and right hand side, is neither a relation nor a function
what is the slope in the linear equation y = 2x=1?
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
A graph shows minutes on the horizontal axis from 0 to 10 and miles from start on the vertical axis from 0 to 1.5. The blue line labeled Andy begins at 0 miles in 0 minutes and ends at 1.25 miles at 10 minutes. The red line labeled Berta begins at 0.5 in 0 minutes and ends at 1.12 miles in 10 minutes. The green line labeled Caedin begins at 1.5 miles in 0 minutes, to 0 miles in 6 minutes, and ends at 1 mile in 10 minutes. [NOTE: character count is 425; possible visual bias in graph]
Three runners run along a 1.5 mile trail one Saturday morning. The graph shows the runners’ locations starting at 9:00 a.m.
Answer:
Who is at the trail start at 9:00 a.m.? : Andy
Who runs fastest? : Caedin
When do Andy and Berta cross paths? : 9:08 am
Who is closest to the 1.5 mile mark after 6 minutes? : Berta
Step-by-step explanation:
assignment
What is 150% of 90?
please explain.
Answer: 135
Step-by-step explanation: Write 150% as 150/100
Since, finding the fraction of a number is same as multiplying the fraction with the number, we have 150/100 of 90= 150/100 X 90
Therefore, the answer is 135
If you are using a calculator, enter 150÷100×90 which will give you 135 as the answer.
150 percentage of 90 is 135 which we obtained by multiplying 1.5 with 90.
"Percent" means "per hundred," so when we say "150%," it means 150 per hundred or 150 out of 100.
To find 150% of 90, we can use the following formula:
150% of 90 = (150/100) × 90
Convert 150% to a decimal.
To do this, divide 150 by 100:
150/100 = 1.5
Multiply the decimal value by 90:
1.5 × 90
= 135
So, 150% of 90 is 135 which means that 135 is 150% of 90, which is equivalent to saying that 135 is 1.5 times larger than 90.
To learn more on Percentage click:
https://brainly.com/question/24159063
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find the largest 5 digit number which is a perfect square
Answer:
Hello,
[tex]316^2=99856[/tex]
Step-by-step explanation:
Since
[tex]\\\sqrt{99999} =316,22618...\\\\The\ largest\ 5\ digit\ number\ which\ is\ a \ perfect\ square\ is\ 316^2=99856}\\[/tex]
Find the values of x and y if (-x + 5, 1) = (-y, 2x - 5y).
Answer:
x = 8, y = 3
Step-by-step explanation:
Equating corresponding x and y coordinates , then
- y = - x + 5 ( multiply through by - 1 )
y = x - 5 → (1)
2x - 5y = 1 → (2)
Substitute y = x - 5 into (2)
2x - 5(x - 5) = 1 ← distribute and simplify left side
2x - 5x + 25 = 1
- 3x + 25 = 1 ( subtract 25 from both sides )
- 3x = - 24 ( divide both sides by - 3 )
x = 8
Substitute x = 8 into (1) for corresponding value of y
y = 8 - 5 = 3
Find the height of the triangle by applying formulas for the area of a triangle and your knowledge about triangles.
This is a triangle. side a has a length of 6 yards. side b has a length of 10 yards. side c has a length of 14 yards. The altitude to side c has a length of X yards. what is x
Answer:
3.71 yd
Step-by-step explanation:
Heron's formula:
area = 0.25 * √((a + b + c) * (-a + b + c) * (a - b + c) * (a + b - c))
so h = 0.5 * √((a + b + c) * (-a + b + c) * (a - b + c) * (a + b - c)) / c
a = 6
b = 10
c = 14
a+b+c = 30
-a+b+c = 18
a-b+c = 10
a+b-c = 2
x = h = 0.5×sqrt(30×18×10×2)/14 = sqrt(30×18×10×2)/28 =
= sqrt(10800)/28 = sqrt(400×9×3)/28 =
= 20×3×sqrt(3)/28 = 60×sqrt(3)/28 = 15×sqrt(3)/7 =
= 3.711537 yd
