if x=2+√5 find the value of x²-1/x²

Answers

Answer 1

Answer:

[tex]{ \tt{ {x}^{2} - \frac{1}{ {x}^{2} } }} \\ = { \tt{ {(2 + \sqrt{5} )}^{2} - \frac{1}{ {(2 + \sqrt{5}) }^{2} } }} \\ = { \tt{ \frac{(2 + \sqrt{5} ) {}^{4} - 1}{ {(2 + \sqrt{5} )}^{2} } }} \\ = { \tt{ \frac{(9 + 4 \sqrt{5}) {}^{2} }{ {(9 + 4\sqrt{5}) }}}} \\ = { \tt{9 + 4 \sqrt{5} }}[/tex]

Answer 2

Answer:

[tex]8\sqrt{5}[/tex]

Step-by-step explanation:

[tex]x = 2 + \sqrt{5}\\\\ x^{2} = (2+ \sqrt{5})^{2} \\\\ \ \ \ \ = 2^{2}+2* \sqrt{5}*2+( \sqrt{5})^{2}\\\\[/tex]

 [tex]= 4 + 4 \sqrt{5}+5\\\\= 9+4 \sqrt{5}[/tex]

[tex]\frac{1}{x^{2}}=\frac{1}{9+4\sqrt{5}}\\\\=\frac{1*(9-4\sqrt{5}}{(9+4\sqrt{5})(9-4\sqrt{5})}\\\\=\frac{9-4\sqrt{5}}{9^{2}-(4\sqrt{5})^{2}}\\\\=\frac{9-4\sqrt{5}}{81-4^{2}(\sqrt{5})^{2}}\\\\=\frac{9-4\sqrt{5}}{81-16*5}\\\\=\frac{9-4\sqrt{5}}{81-80}\\\\=\frac{9-4\sqrt{5}}{1}\\\\=9-4\sqrt{5}[/tex]

[tex]x^{2}-\frac{1}{x^{2}}= 9 + 4\sqrt{5} -(9 - 4\sqrt{5})\\\\[/tex]

            [tex]= 9 + 4\sqrt{5} - 9 + 4\sqrt{5}\\\\= 9 - 9 + 4\sqrt{5} + 4\sqrt{5}\\\\= 8\sqrt{5}[/tex]


Related Questions

help me please it's important!!​

Answers

Answer:

Does the answer help you?

Answer:

102 cm³

Step-by-step explanation:

Volume of R1:

length = 7 cm

Width = 3 cm

Height = 2 cm

Volume = 7* 3  * 2 = 42 cm³

Volume of R2:

length = 5 cm

Width = 4 cm

Height = 3 cm

Volume = 5 * 4 * 3=  60 cm³

Volume of the figure = 42 + 60 =  102 cm³

If P =
1 2
then, prove that P2 - 2P - 5 = 0, 1 = 0, where I and 0 are unit
3 1
matrix and null matrix of order 2 x 2 respectively.

Answers

Answer:

thanks for free ponits you dint gave it free but I theft I'm sorry

The volume of this cube is 64 cubic feet. What is the value of a?

Answers

Answer:

a = 4 feet

Step-by-step explanation:

Since it's a cube, we know that each value will be equal. Because of this, you can cube root the cube's volume to find a.

[tex]\sqrt[3]{64}=4[/tex]

Therefore, a = 4 feet.

Answer:

4

Step-by-step explanation:

To find the area of a cube, we have to multiply the width, height, and length, which, since they are all the same value, would be a side multiplied by itself 3 times(cubed). So, the area of this cube in terms of a(side) is a*a*a or a^3. The area is given to be 64, so we can write:

a^3 = 64

With the equation, we can realize 4*4*4 is 64, meaning a is 4.

Which shapes have the greatest area?
(Select all that apply.)

Answers

Answer:

the trapiezium

Step-by-step explanation:

It has a area of 4 which is the highest

The path from the subway station to the art museum is three blocks to the north then four blocks to the west.
What is the straight-line distance in blocks from the subway station to the art museum?

Answers

Answer:

7 block s

Step-by-step explanation:

3 from North plus

4 from West

4+3=7

9/7 = please answer me​

Answers

Answer:

[tex] \frac{9}{7} = 1.2857 = 1 \frac{2}{7} [/tex]

Answer:

Step-by-step explanation:

[tex]\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\la\la\la\la\ddddddddddddddddddddddddddddddddcleverdddddd\ffffffffffffffffffffffffffffffffffffffff\pppppppppppppppppppppppppppppppppppp\ddddddddddddddddddd\displaystyle\ \Large \boldsymbol {\frac{9}{7}=1\frac{2}{7} \ \ or \ \ 1.(28571)}[/tex]

Below are two different functions, f(x) and g(x). What can be determined about their slopes? f(x)= 4x + 2 The function g of x going through 0, negative 2 and 1, 3 (1 point) The function f(x) has a larger slope. The function g(x) has a larger slope. They both have the same slope. The relationship between slopes cannot be determined.

Answers

Answer:

g(x) has the larger slope.

Step-by-step explanation:

f(x) = 4x + 2

- so its slope = 4.      ( from general form y = mx + c where m = slope).

The slope of g(x) = (3 - (-2) / (1 - 0)

= 5.

Find the number in which 9 has greater value.
0.5689
5.6890
56.89
569.80

Answers

Answer:

569.80

Step-by-step explanation:

Among all the choices, the digit 9 has the greatest value in number 569.80. For the reason that 9 got ones value - which are greatest than other.

[tex]\tt{ \green{P} \orange{s} \red{y} \blue{x} \pink{c} \purple{h} \green{i} e}[/tex]

Find the measure of the indicated angle to the nearest degree.

Answers

Answer:

Step-by-step explanation:

Adjacent to the undetermined angle is 6, and the hypotenuse has been given. We can conclude, after looking at our SOHCAHTOA, that we will be using cosine(CAH) to solve this problem.

Let the unspecified angle be [tex]\theta\\[/tex] (This sign is called theta, which is just a sign for angle)

Lets start!

cos[tex]\theta\\[/tex] = adj/hyp

cos[tex]\theta\\[/tex] = 6/13

[tex]\theta\\[/tex] = [tex]cos^{-1}[/tex](6/13)

[tex]\theta\\[/tex] = 62.5

[tex]\theta\\[/tex] = 63

Hope that helped!

(x^2+1)(x-1)=0 help me pls

Answers

Answer:

x = ±i ,  x=1

Step-by-step explanation:

(x^2+1)(x-1)=0

Using the zero product property

x^2 +1 = 0   x-1= 0

x^2 = -1       x=1

Taking the square root of the equation on the left

sqrt(x^2) = sqrt(-1)

x = ±i   where  i is the imaginary number

We still have x=1 from the equation on the right


Which number is a solution of the inequality?
3x - 15 ≥ 3

a.) -9/11

b.)6/11

c.)6

d.)5

Answers

Answer:

6

Step-by-step explanation:

[tex]3x - 15 \geqslant 3[/tex]

[tex]3x \geqslant 3 + 15[/tex]

[tex]x \geqslant \frac{18}{3} [/tex]

[tex]x \geqslant 6[/tex]

Which is the equation of a parabola with Vertex (0,0) and focus (0, 2)?
a. ya = 8x
c. x2 = 8
b. y2 = 4x
d. x2 = 4y

Answers

Answer:

So the equation of the parabola is x2=8y i don't really know

A P E X fasted answer is getting 30 points please hurry.

suppose a normal distribution has a mean of 98 and a standard deviation of 6. what is p(x ≥ 92)

Answers

Answer:

Step-by-step explanation:

If the mean is 98 and standard deviation is 6, then 92 is one standard deviation to the left of the mean; that means that 34% + 34% + 13.5% + 2.35% + .15% of the data is included in this area. Add those up and you get, as a percentage, 84%.

Answer:

0.84

Step-by-step explanation:

yee its right

Which of the following planets has the strongest winds in the solar system?
O Jupiter
O Mars
O Neptune
O Venus

Answers

Neptune has the strongest winds in the Solar System. Winds whip clouds of frozen methane across the planet at speeds of more than 1,200 miles per hour (2,000 kilometers per hour).

Answer: The answer is Neptune ^-^

Step-by-step explanation:

Got it correct on the test :]

A cylindrical paint can has a diameter of 12 centimeters and height of centimetrs which is closest to the volume of the paint can in cubic centimeters

Answers

Answer:

The correct answer is "1808.64 cm³".

Step-by-step explanation:

Seems that the given query is incomplete. Below find the attachment of the complete problem.

Given:

Diameter,

d = 12 cm

Radius,

r = [tex]\frac{d}{2}[/tex]

 = [tex]\frac{12}{2}[/tex]

 = [tex]6 \ cm[/tex]

Height,

h = 16 cm

As we know,

The volume of cylinder is:

= [tex]\pi r^2 h[/tex]

By substituting the values, we get

= [tex]3.16\times (6)^2\times 16[/tex]

= [tex]3.14\times 36\times 16[/tex]

= [tex]1808.64 \ cm^3[/tex]

according to the rational root theorem which of the following are possible roots of the polynomial function below? F(x)=6x^3-7x^2+2x+8

Answers

Answer:

Hello,

Step-by-step explanation:

all potential roots are of the form a/b where a is a divisor of 8

and b is a divisor of 6 ( in Z)

So A,D,E,F may be roots

but B and C not.

Kristina wants to buy a flute that costs 240 . She has saved 20 each week for 3 weeks . How many more weeks does Kristina need to save money if she continues to save 20 each week

Answers

Answer:

9 more weeks

Explanation:

She already saved 20(3)=60

240=60+20(x)
X=9
She needs 9 more weeks

PLS HELP WILL MAKE FIRST RIGHT ANSWER GETS BRAINLIEST ​

Answers

Answer:
26. A
27. A

Explanation:

The distributive property can be applied to which expression to factor 12x3 – 9x2 + 4x – 3?
3(4x3– 1) – (9x2 + 4x)
4x(3x2 + 1) – 3(3x2 – 1)
3x(4x – 3) – (3+ 4x)
3x2(4x – 3) + 1(4x – 3)
IM ON EDGE

Answers

Answer:

12x^3-9x^2+4x-3

3(4x^3-1)-(9x^2+4x)

therefore option A is right

thank you, and mark it as brainliest if u find it useful

find the measure of one exterior angle for the following regular polygon ​

Answers

Answer:

36 degrees

Step-by-step explanation:

10 corners/sides.

the sum of all exterior angles in a polygon is always 360 degrees.

so, one exterior angle here is 360/10 = 36 degrees

Complete the table, and then use the drawing tools to create the graph representing the relationship between the amount of plant food remaining, f(x), and the number of days that have passed, x.

Answers

The complete table of the function is:

[tex]\begin{array}{cccccccc}x & {0} & {1} & {2} & {3} & {4}& {5} & {6} \ \\ f(x) & {72} & {60} & {48} & {36} & {24}& {12} & {0} \ \end{array}[/tex]

The equation missing from the question is:

[tex]y = 72 - 12x[/tex]

To complete the table, we simply calculate the y value for each x value;

When [tex]x = 0[/tex],     [tex]y = 72 - 12 * 0 = 72[/tex]

When [tex]x = 1[/tex],     [tex]y = 72 - 12 * 1 = 60[/tex]

When [tex]x = 2[/tex],     [tex]y = 72 - 12 * 2 = 48[/tex]

When [tex]x = 3[/tex],     [tex]y = 72 - 12 * 3 = 36[/tex]

When [tex]x = 4[/tex],     [tex]y = 72 - 12 * 4 = 24[/tex]

When [tex]x = 5[/tex],     [tex]y = 72 - 12 * 5 = 12[/tex]

When [tex]x = 6[/tex],     [tex]y = 72 - 12 * 6 = 0[/tex]

So, the complete table is:

[tex]\begin{array}{cccccccc}x & {0} & {1} & {2} & {3} & {4}& {5} & {6} \ \\ f(x) & {72} & {60} & {48} & {36} & {24}& {12} & {0} \ \end{array}[/tex]

To create a graph of f(x), we simply type [tex]y = 72 - 12x[/tex] on a drawing tool and the graph will be generated.

See attachment for graph

Learn more about graphs at:

https://brainly.com/question/20106471

Answer:

Step-by-step explanation:

Darryl has written 60 percent, or 12 pages, of his history report. Darryl wants to figure out how many total pages he needs to write. Darryl’s work is shown below.
Step 1: Write 60 percent as a ratio. StartFraction part Over whole EndFraction = StartFraction 60 Over 100 EndFraction

Answers

Answer:

total pages = 20

Step-by-step explanation:

60% of an unknown number is 12

Let the unknown number (total pages) be x.

60/100 of x = 12

60/100 * x = 12

3/5 x = 12

x = 12 * 5/3

x = 20

Total page equals 20 your welcome my friend

find the missing length indicated​

Answers

Answer:

192

Step-by-step explanation:

Apply the geometric mean formula to solve for x, which is the altitude of the right triangle.

The formula is:

h = √(mn)

h = x = ?

m = 144

n = 400 - 144 = 256

Substitute

h = √(256*144)

h = √36,864

h = 192

Therefore, x = 192

PLEASE HELP ASAP!!!!! The following graph shows a proportional relationship. What is the constant of proportionality between y and x in the graph?

Answers

Answer:

2/3

Step-by-step explanation:

The graph point is on (3,2)

the best way to learn math formulas

Answers

Writing down the formulas on charts and pasting it in your room,by seeing this daily it helps to memorize the formulas.

Saying the formulas louder also helps to memorize the formula.

Watching videos related to maths formulas and equations helps to remember the formulas easier.

Doing many problems regularly will helps you to remember the formulas.

lastly study to Understand The Formula not to memorize

5. There are 5,280 feet in a mile. What part of a mile, in decimal form, will you drive until you reach the exit? I NEED THIS QUICK PLZ HELP I’LL GIVE YOU 30

Answers

Brainlist me!! :) hope this helps you

Answer:

5.280

Step-by-step explanation:

i did this question and got it

8.52 The heights of 2-year-old children are normally distributed with a mean of 32 inches and a standard deviation of 1.5 inches. Pediatricians regularly measure the heights of toddlers to determine whether there is a problem. There may be a problem when a child is in the top or bottom 5% of heights. Determine the heights of 2-year-old children that could be a problem.

Answers

Answer:

Heights of 29.5 and below could be a problem.

Step-by-step explanation:

Normal Probability Distribution

Problems of normal distributions can be solved using the z-score formula.

In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

The heights of 2-year-old children are normally distributed with a mean of 32 inches and a standard deviation of 1.5 inches.

This means that [tex]\mu = 32, \sigma = 1.5[/tex]

There may be a problem when a child is in the top or bottom 5% of heights. Determine the heights of 2-year-old children that could be a problem.

Heights at the 5th percentile and below. The 5th percentile is X when Z has a p-value of 0.05, so X when Z = -1.645. Thus

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]-1.645 = \frac{X - 32}{1.5}[/tex]

[tex]X - 32 = -1.645*1.5[/tex]

[tex]X = 29.5[/tex]

Heights of 29.5 and below could be a problem.

If the lengths of the legs of a right triangle are 4 and 8, what is the length of the hypotenuse?

PLEASE HELP

Answers

Answer:

[tex]4\sqrt{5}[/tex]

Step-by-step explanation:

In order to solve this problem, we can use the pythagorean theorem, which is

a^2 + b^2 = c^2, where and b are the legs of a right triangle and c is the hypotenuse. Since we are given the leg lengths, we can substitute them in. So, where a is we can put in a 4 and where b is we can put in an 8:

a^2 + b^2 = c^2

(4)^2 + (8)^2 = c^2

Now, we can simplify and solve for c:

16 + 64 = c^2

80 = c^2

c = [tex]\sqrt{80}[/tex]

Our answer is not in simplified radical form because the number under is divisible by a perfect square, 16. We can divide the inside, 80,  by 16, and add a 4 on the outside, as it is the square root of 16:

c = [tex]4\sqrt{5}[/tex]

The length of the hypotenuse in the given right triangle, with legs measuring 4 and 8, is approximately 8.94.

To find the length of the hypotenuse in a right triangle, we can use the Pythagorean theorem. According to the theorem, in a right triangle, the square of the hypotenuse's length is equal to the sum of the squares of the lengths of the other two sides.

In this case, let's label the lengths of the legs as 'a' and 'b', with 'a' being 4 and 'b' being 8. The hypotenuse, which we need to find, can be represented as 'c'.

Applying the Pythagorean theorem, we have:

[tex]a^2 + b^2 = c^2[/tex]

Substituting the given values:

[tex]4^2 + 8^2 = c^2[/tex]

16 + 64 = [tex]c^2[/tex]

80 = [tex]c^2[/tex]

To find the length of the hypotenuse 'c', we need to take the square root of both sides:

√80 = √ [tex]c^2[/tex]

√80 = c

The square root of 80 is approximately 8.94.

Therefore, the length of the hypotenuse in the given right triangle, with legs measuring 4 and 8, is approximately 8.94.

To know more about  hypotenuse , here

https://brainly.com/question/2217700

#SPJ2

Write the equation of the line that passes through the points (−7,5) and (-7,-8).
Put your answer in fully reduced point-slope form, unless it is a vertical or horizontal line.

Answers

Answer:

x = -7

Step-by-step explanation:

First we find the slope using

m = ( y2-y1)/(x2-x1)

   = ( -8 - 5)/( -7 - -7)

   = (-8-5)/(-7+7)

   = -13/0

This means the slope is undefined and the line is vertical

Vertical lines are in the form

x= constant and the constant is the x value of the points

x = -7

Tyrone measured the floor of his rectangular storage unit. It is 3 feet wide and 8 feet from one corner to the opposite corner. How long is the storage unit? If necessary, round to the nearest tenth.

Answers

Answer:

Rounded to the nearest tenth, 7.4 feet long.

Step-by-step explanation:

Tyrone has a rectangular storage unit. We are given the width and the diagonal length.

So we can use Pythagorean Theorem.

3^2 + b^2 = 8^2

9 + b^2 = 64

subtract 9 from both sides

b^2 = 55

b = sqrt55

b is around 7.4161984871, so b rounded to the nearest tenth is 7.4 feet long.

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