Express each sum in sigma-notation

1 + 1/4 + 1/9 + 1/16 + ... + 1/400

Answers

Answer 1

9514 1404 393

Answer:

  [tex]\displaystyle\sum\limits_{n=1}^{20}{\dfrac{1}{n^2}}[/tex]

Step-by-step explanation:

We notice that the denominator of each term is the square of the term number, so the last term must be the 20th. The sum is then ...

  [tex]\displaystyle\sum\limits_{n=1}^{20}{\dfrac{1}{n^2}}[/tex]


Related Questions

Stephen goes to the fair and buys two funnel cakes and one drink. His total bill is $6.75. A few days later, he goes with a friend and buys three funnel cakes and two drinks. This time his total bill is $11.

Write two equations that could be used to determine how much each funnel cake and drink costs. Use f for the cost of a funnel cake and d for the cost of a drink.

What is the cost of a funnel cake?

What is the cost of a drink?

Answers

Answer:

Let's define the variables:

f = Cost per cake

d = Cost per drink.

"Stephen goes to the fair and buys two funnel cakes and one drink. His total bill is $6.75. "

2*f + 1*d = $6.75

"A few days later, he goes with a friend and buys three funnel cakes and two drinks. This time his total bill is $11."

3*f + 2*d = $11.

Then we have a system of equations:

2*f + 1*d = $6.75

3*f + 2*d = $11.

To solve this, the first step is to isolate one of the variables in one of the equations, let's isolate d in the first equation:

d = $6.75 - 2*f

Now we can replace this in the other equation:

3*f + 2*($6.75 - 2*f) = $11

3*f - 4*f + $13.50 = $11

-f = $11 - $13.50 = -$2.50

f = $2.50

Then the cost of a funnel cake is $2.50

And the cost of a drink can be obtained with the equation:

d = $6.75 - 2*f = $6.75 - 2*$2.50 = $1.75

The cost of a drink is $1.75

Find the number whose arithmetic square root is 0.6

Answers

Answer: 0.36

Step-by-step explanation:

6/10 x 6.10= 36/100

Molly opened a bank account. She deposited $86.50 into her account every month for 20 months. She used $24.50 every month to pay for singing lessons. After 20 months, she used 1 over 4 of the total money left in her account to go to a summer camp for singers. What is the total amount of money Molly spent to go to the summer camp?

Answers

Answer:$310

Step-by-step explanation:

A company manufactures fuel tanks for cars. The total weekly cost (in dollars) of producing x fuel tanks is given by ... C(x) = 10000 +90x - 0.08x2 Find the exact cost of producing the 501st item.

Answers

Answer:

cost of producing the 501st item = $9.92

Step-by-step explanation:

The function representing the cost is given by;

C(x) = 10000 + 90x - 0.08x²

To get the cost of producing the 501st item, we have to first find the cost of producing 500 items and then do the same for 501 items then subtract the values gotten.

Thus;

C(500) = 10000 + 90(500) - 0.08(500)²

C(500) = 10000 + 45000 - 20000

C(500) = $35000

Similarly;

C(501) = 10000 + 90(501) - 0.08(501)²

C(501) = 10000 + 45090 - 20080.08

C(501) = $35009.92

cost of producing the 501st item = C(501) - C(500) = 35009.92 - 35000 = $9.92

write an equation of the line with a slope of -3/4 and y-intercept of -6

Answers

Answer:

y = -3/4x - 6

Step-by-step explanation:

Answer: y = (-3/4)x - 6

The sum of 2x50 and 3x50 is ____ x 50?

Answers

5

Simply add 3 and 2. You dont need to worry about the 50.

Or, complete 2x50 and 3x50

Now you would have 100 and 150.

Then add them to get 250.

Finally, divide 250 by 50.

Your answer should be 5

x+ y + z = -3
3y - Z = 4
2x- y - 2z = -5

Answers

Answer:

(-3, 1, -1)

Step-by-step explanation:

x + y + z = -3  --> (1) 3y - z = 4   --> (2)2x - y - 2z = -5 --> (3)

Add up (1) and (2)

x + 3y + y + z - z = -3 + 4 ⇒ x + 4y = 1  --> (4)

Double (2) and subtract from (3)

2x - y - 2z - 2(3y - z) = -5 - 2(4) ⇒ 2x - y - 2z - 6y + 2z = -5 - 82x - 7y = -13 --> (5)

Double (4) and subtract (5)

2(x + 4y) - 2x + 7y = 2 + 13 ⇒ 2x + 8y - 2x + 7y = 15 ⇒ 15y = 15 ⇒ y = 1

Finding x

x + 4(1) = 1 ⇒ x = 1 - 4  ⇒ x = -3

Finding z

-3 + 1 + z = -3 ⇒ z = -1

So the answer is:

(-3, 1, -1)

While at the pet store, Fred counted the number of animals in the store. For every 3 dogs in the store, there were 4 cats. Identify the equivalent ratios of dogs to cats. Select two that apply. 6:8 B 300:40 C 9:12 D 6:2​

Answers

A and C would be your answer because
3x2= 6
4x2=8.
And
3x3=9
4x3=13

Answer:

I am thinking that it is A and C

Step-by-step explanation:

If I am right may I get a brailiest

If I am wrong I am so very sorry

A rectangular poster is 50 cm long and 25 cm wide. If 1 cm is approximately .4 inches What is the perimeter of the poster

Answers

It will be 600in or 150cm.
Reason is perimeter is just adding up the sides so if you wanna find it in inches then you multiply 4 by each side and if it’s just cm then just add them all up

Solve for x.
14 = 28 + 7x

Answers

Answer:

X = 2

Step-by-step explanation:

14= 28 + 7x

28 - 14 = 7x

14 = 7x

14 / 7

2 = x

Answer:

x  =  − 2

Step-by-step explanation:

An open-top box is to be made from a 12-inch by 24-inch piece of plastic by removing a square from each corner of the plastic and folding up the flaps on each side. What is the maximum possible volume, in cubic inches, of the box?

Answers

Answer:

The maximum possible volume = 332.685 cubic inches

Step-by-step explanation:

From the information given:

Let the height be = x

The length be = 24 - 2x

The width be = 12 - 2x

Then V = x (24 -2x) ( 12 - 2x)

V = x ( 288 -48x - 24x +4x²)

V = x(288 - 72x + 4x²)

V = 288x - 72x² + 4x³

[tex]\dfrac{dV}{dx}= (3x^2 - 36x+ 72)[/tex]

[tex]\implies x^2 - 12x + 24 = 0[/tex]

[tex]=\dfrac{-b \pm \sqrt{b^2 - 4ac}}{2a}[/tex]

[tex]=\dfrac{-(-12) \pm \sqrt{(-12)^2 - 4(1)(24)}}{2(1)}[/tex]

[tex]=\dfrac{12 \pm \sqrt{144 - 96}}{2}[/tex]

[tex]=\dfrac{12 \pm \sqrt{48}}{2}[/tex]

where;

[tex]x \ne \dfrac{12 + \sqrt{48}}{2}[/tex]

∴ [tex]x= \dfrac{12 - \sqrt{48}}{2}[/tex]

x = 2.536 ( since the length cannot be negative)

So, the length x = 24 - 2(2.535) = 18.93

The width = 12 - 2(2.535) = 6.93

heigth = 2.536

V = 18.93 ×  6.93 ×  2.536

V = 332.685 cubic inches

    A box is made from a plastic sheet by removing square from each corner, maximum volume of this box will be 332.55 cubic inches.

Volume of a cuboid:   Volume of a cuboid or rectangular box is given by the expression,

           Volume = Length × Width × Height

Given in the question,

   Plastic sheet with length = 12 inches    Width of the sheet = 24 inches    A square has been removed from each corner to fold the box.

Let the measure of each side of a square removed = x inches

Therefore, length of the box = (12 - 2x) inches

Width of the box = (24 - 2x) inches

Height of the box = x inches

Volume of the box (V) = (12 - 2x) × (24 - 2x) × (x)

                                V  =  4x³ - 72x² + 288x

To find the maximum volume of the box differentiate the expression with respect to 'x' and equate it to zero.

V' = 12x² - 144x + 288

For V' = 0,

12x² - 144x + 288 = 0

x² - 12x + 24 = 0

[tex]x=\frac{12\pm\sqrt{(12)^2-4(1)(24)} }{2(1)}[/tex]

[tex]x=(6\pm2\sqrt{3})[/tex]

[tex]x=9.46,2.54[/tex]

For x = 9.46,

Volume of the box = 4(9.46)³- 72(9.46)² + 288

                               = -2769.03 cubic inches

For x = 2.54,

Volume of the box = 4(2.54)³- 72(2.54)² + 288

                               =  332.55 cubic inches

       Therefore, maximum volume of the box will be 332.55 cubic inches.

Learn more about the volume of a cuboid here,

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A fish makes 480 dives on 10 hours at this rate how many dives did the fish do in 4 hours

Answers

Answer: 1200

Step-by-step explanation:

Answer:

192

Step-by-step explanation:

First, you would divide 480 by 10 to get 48 because you divide by the number of hours.

Then, multiply 48 by 4 to get your answer.

The answer: 192

12x+2y=-12 in slope form

Answers

Answer:

y = -6x - 6

General Formulas and Concepts:

Pre-Algebra

Equality Properties

Algebra I

Standard Form: Ax + By = C

Slope-Intercept Form: y = mx + b

m - slope b - y-intercept

Step-by-step explanation:

Step 1: Define

Standard Form:   12x + 2y = -12

Step 2: Rewrite in slope-intercept form

Subtract 12x on both sides:                    2y = -12x - 12Divide 2 on both sides:                           y = -6x - 6

which of the following can be used to show that these triangles are congruent?

Answers

Answer:

ASA

Step-by-step explanation:

Angle B side BC and angle C

Triangle ABC and CDE are congruent by ASA congruence. Therefore, option E is the correct answer.

In the given figure, ΔABC and ΔCDE.

What is the congruence theorem?

Triangle congruence theorem or triangle congruence criteria help in proving if a triangle is congruent or not. The word congruent means exactly equal in shape and size no matter if we turn it, flip it or rotate it.

Here,

Consider ΔABC and ΔCDE, we get

∠B = ∠E (Given)

BC=CE (Given)

∠BCA = ∠ECD (Vertically opposite angles)

By ASA congruence, ΔABC≅ΔCDE

Triangle ABC and CDE are congruent by ASA congruence. Therefore, option E is the correct answer.

To learn more about the congruent theorem visit:

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Find the exact volume of a waffle ice cream cone with 15-in. Diameter and a height of 23 inches

Answers

Radius = 15/2 = 7.5
Volume of cone: pi(r)^2*h/2
= pi(7.5)^2*23/2
pi(56.25) * 23/2
(3.14)(56.25)(23)/2 = 2,031 inches

Question 3 :
Furniture of vendor firm recorded in
the books at Rs.2,50,000, were taken
over by the partner at an agreed
value of Rs.1,75,000, the amount to
be debited to partners' capital
account will be:
Rs. 2,50,000
Rs.75,000
Rs.4,25,000
Rs. 1,75,000

Answers

Answer:

Rs. 2,50,000

Step-by-step explanation:

When a partnership distributes inventory items (hot asset) to its partners, the basis of the inventory items is used to record the transaction. Only when partnerships distribute assets other than hot assets will the fair market value of the assets be used to record the transaction.

The logic is that inventory items are valued at lower of cost or market value. This means that inventory items are already valued at FMV or cost, whichever is less. If the partnership recorded the transaction using Rs.1,75,000, then it would have to record a loss, and distributions cannot generate losses to a partnership. The only way to record the inventory items at Rs.1,75,000 is that previously the partnership writes down inventory.

the square of a number equals five times that number find number.
A. 0 or 1
B. 0 or 3
C. 0 or 5
D. 0 or 7​

Answers

Answer:

x²=5x

x=5... probably c

A rectangle is 3/5 red. The rest is blue and yellow, but not in equal ratios. What could those ratios be? PLEASE HELP

Answers

Blue can be 1/10 and yellow can be 3/10 or other way around.

Can anyone please help FAST! I’m looking for the correct answer and how you explain it! I’ll mark brainlist please and thank you!

Answers

1a. Y = mx + b
Y = 2x + b
-2 = 2(5) + b
-2 = 10 + b, b = 12
Equation: y = 2x + 12

1b. Standard form: Ax + By = C
subtract 12 and y from both sides
2x - y = -12
Equation: 2x - y = -12

Answer:

Part 1: y=2x-12

Part 2: 12=2x-y

Step-by-step explanation:

Given Information:

m (slope) = 2

There is a point: (5, -2)

PART 1

Solution: Use the formula:  [tex]y=m(x-x_{1} )+y_{1}[/tex]

y=2(x-(5))+(-2)

y=2x-10-2

y=2x-12

PART 2

y=2x-12         (from part 1)

0=2x-y-12      

12=2x-y

What is the volume, measured in cubic centimeters, of the box below? Do not
include units in your answer.
4 cm
5 cm
1 cm

Answers

Answer:

20

Step-by-step explanation:

4 × 5 × 1 = 20 (cm³)

Hope it help, please give me Brainlest!

Answer:

20

Step-by-step explanation:

The formula for volume:

[tex]V=length*width*height\\\\V=lwh[/tex]

Multiply all given values together:

[tex]V=4*5*1\\\\V=20*1\\\\V=20[/tex]

The volume of the box is 20cm³.

:Done

Note:

"Cubic" centimeters means cm³. The exponent is used because you multiplied 3 dimensions.

Another example would be with area. To find this, you multiply length by width, resulting in area², because you mutliplied 2 dimensions.

In this diagram lines AB and CD are Parallel

Answers

Answer: I need a picture to find out ;-;

Step-by-step explanation:

Answer:

if youre asking for the equation its AB=CD

Step-by-step explanation:

If youre not, you'll need to attach a file or smth :'D

Help please I am begging

Answers

Answer:

The answer is A, 3.50w.

Step-by-step explanation:

When there is 1 pound, it is 3.50. 2 pounds it's 7.00 which is 3.50 times 2.

If this helped I would appreciate it if you marked me Brainliest. thank you and have a nice day!

The temperature was 12°C before the storm. During the storm, the temperature dropped 19°C. What was the temperature at the end of the storm?​

Answers

Answer:

-7 degrees celsius

Step-by-step explanation:

12-19=-7

Answer:

-7

Step-by-step explanation:

12 - 19 = -7

A taxi ride costs $4 plus an additional $3 per mile. Write the equation for the line in slope-intercept form

Answers

Answer:

y=3x+4

Step-by-step explanation:

4 is your y-intercept, and 3 is your slope.

The linear function shows the total cost will be y = 3x + 4.

What is a linear function?

A straight line on the coordinate plane is represented by a linear function.

A linear function always has the same and constant slope.

The formula for a linear function is f(x) = ax + b, where a and b are real values.

As per the given,

A taxi ride costs $4 plus an additional $3 per mile.

Let's say the number of miles is represented as x while the total cost is represented as y.

y = 3x + 4

Hence "The linear function shows the total cost will be y = 3x + 4".

For more about the linear function,

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Which of the following shows the best communicative property of addition ?
4+5=4-(-5)
4+5=9
4+5=5+4
4+5=4+(2+3)

Answers

Answer:

In the given options, 4+5 = 5+4 shows the best commutative property.

Step-by-step explanation:

One of the properties that can be applied on numbers is commutative property. Commutative property states that the order of the numbers on which any operation is being performed, can be swapped and the answer won't change.

Commutative property can be applied on addition, subtraction and multiplication.

Commutative property of Addition:

Commutative property of addition states that changing the order of adding two numbers does not change the result i.e. a+b = b+a

In the given options, 4+5 = 5+4 shows the best commutative property.

Which of the following describes the following graph?

A. Function only
B. Relation only
C. Neither funtion or relation
D. Both a function and a relation

Answers

The answer is A for the correct answer

y=_x+_ what would be the answer​

Answers

Answer:

y = -1/4x + 2

Step-by-step explanation:

slope = rise over run

-1 rise for 4 run

y intercept = 2

y = -1/4x + 2

In a semiconductor company's quality control test, a machine found that 14 out of a sample of 234 computer chips were defective. How many of the 4705 such chips that the company makes each month would you expect to be defective?

Answers

Answer:

281-282

Step-by-step explanation:

An N-scale model railroad caboose is 3 inches long. N scale is 169 feet to 1 foot.


Let c represent the length of a real caboose. Write a proportion, in terms of c, that can be used to solve for the length of a real caboose. (Hint: Compare feet to inches. How many inches are in one foot?)


How long (in feet) is a real caboose?

ft

Answers

9514 1404 393

Answer:

c/3 = 169/1242 1/4 feet

Step-by-step explanation:

Since we want to know the actual number of feet, we can write the proportion with that in the numerator.

  [tex]\dfrac{\text{actual feet}}{\text{scale inches}}=\boxed{\dfrac{c}{3}=\dfrac{169}{12}}\\\\c=\dfrac{3\cdot169}{12}=42\frac{1}{4}\qquad\text{multiply by 3}[/tex]

The real caboose is 42 1/4 feet long.

Find the PERCENT of change.
20 dogs to 5 dogs

Answers

Answer:

75%

Step-by-step explanation:

20-5=15 - change in numbers

15/20×100%= 75%

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