Find a formula for the sum of the first n even integers : 2 + 4 + 6 + ... + 2n.

Answers

Answer 1

Let S be the sum,

S = 2 + 4 + 6 + ... + 2 (n - 2) + 2 (n - 1) + 2n

Reverse the order of terms:

S = 2n + 2 (n - 1) + 2 (n - 2) + ... + 6 + 4 + 2

Add up terms in the same positions, so that twice the sum is

2S = (2n + 2) + (2n + 2) + (2n + 2) + ... + (2n + 2)

or

2S = n (2n + 2)

Divide both sides by 2 to solve for S :

S = n (n + 1)


Related Questions

right triangles to find the exact length of:
T
30°
14 in
a) TI = in
60°
R

Answers

Answer:

a) TI = 7√3 in

b) IR = 7 in

Explanation:

Using cosine rule:

[tex]\sf cos(x) = \dfrac{adjacent}{hypotenuse}[/tex]

[tex]\hookrightarrow \sf cos(30) = \dfrac{TI}{14}[/tex]

[tex]\hookrightarrow \sf TI = 14cos(30)[/tex]

[tex]\hookrightarrow \sf TI = 7\sqrt{3}[/tex]

Using sine rule:

[tex]\sf sin(x) = \dfrac{opposite}{hypotenuse}[/tex]

[tex]\hookrightarrow \sf sin(30) = \dfrac{IR}{14}[/tex]

[tex]\hookrightarrow \sf IR = 14sin(30)[/tex]

[tex]\hookrightarrow \sf IR = 7[/tex]

what contribution to geometry is attributed to the work of rene descartes

Answers

Answer: Analytic geometry

which is the greatest 30000 millimeters 1 kilometer 5000 meters or 6000 centimeters?

Answers

5000 meters because it is equal to 5 kilometers which is greater than every other option
1 kilometer = 1 kilometer, 30000 millimeters = .03 kilometers, 5000 meters = 5 kilometers, 6000 centimeters = .06 kilometers. Hope this helps!

The circumference of a circle is 37.68 meters. What is the circle's diameter?
C = 37.68 m
Use 3.14 for л.

Answers

Answer:

The diameter is 12.

Explain: i used this formula C= Dπ  or C= 2rπ  

(37.68) = Dπ Divide by 3.14, as the instructions in this question specify to do so.

37.68/3.14 = D π/ 3.14

D = 12  The diameter equals twelve.

Hope This Helped

Using the cards 3,2,4,7 show a valua closest to 5000

Answers

4,7,3,2

Step-by-step explanation:

THESE ARE THE THE ARRANGEMENT OF NUMBERS IN ORDER TO GET THE CLOSEST TO 5000

Please help me

Find the value of x

Answers

Answer:

x = 5 and y = 22

Step-by-step explanation:

See attached image.

Kevin evaluated the expression below. 75 - 6 (8 - 6) + 3 Step 1: 75 - 6 x 2 + 3 Step 2: 75 - 6 x 5 Step 3: 75 - 30 Step 4: 45 Kevin made an error in solving the expression. What error did Kevin make? Which step contains the error? What error did Kevin make? Explain how you would correct Kevin's error. Be sure to include the correct answer in your explanation.

Answers

The error Kevin made was in step 2 when he added before he multiplied.

What error did Kevin make?

This question would be solved using the BODMAS rule. The BODMAS rule provides the order in which mathematical problems should be solved. The order is:

bracket of division multiplication addition subtraction

Step 1 : 75 - 6 x 2 + 3Step 2: 75 - 12 + 3 Step 3 : 75 - 9 Step 4: 66

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The probability of sandy flipping a coin twice and getting heads both times is 0.25 the probability of john's spinner stopping on the color red is

Answers

The true statement is (c) Neither. Both events are equally likely.

Complete question

The probability of Sandy flipping a coin twice and getting heads both times is 0.25. The probability of John's spinner stopping on the color red is 1/4.

Which of these events is more likely?

-Sandy flips a coin twice and gets heads both times.

-John's spinner stops on the color red.

-Neither. Both events are equally likely.

How to determine the likely event?

The given parameters are:

P(Head twice) = 0.25

P(Red) = 1/4

Rewrite P(Red) as:

P(Red) = 0.25

By comparison, we have:

P(Red) = P(Head twice) = 0.25

This means that both events are equally likely

Hence, the true statement is (c)

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An exponential function contains the points (1, 0.9) and
(2, 1.62). What is an exponential function that contains
these points?

Answers

Answer:

Hi,

Step-by-step explanation:

Let's say y=a*b^x the equation of the exponential function.

0.9=a*b^1 (1)

1.62=a*b² (2)

(2)/(1) ==> b=1.62/0.9=1.8

and

0.9=a*1.8 ==> a=0.5

y=0.5*1.8^x

Use the Distributive Property to write each expression as an equivalent expression. Then evaluate it. 3(5+1)

Answers

Answer:

18

Step-by-step explanation:

[tex]3(5 + 1) \\ 3(5) + 3(1) \\ 15 + 3 \\ 18[/tex]

The distributive property means you distribute the multiple to all terms in the parenthesis, in this case the terms are 5 and 1.

what is the midpoint of (-2, -1) and (0, 9)

Answers

Answer:

(-1,4)

Step-by-step explanation:

For x     the midpoint between   -2 and 0    is -1

for y the midpoint between -1 and 9 is  4

Answer:

(-1,4)

Step-by-step explanation:

Midpoint can be found by:

(x1+x2)/2 ; (y1+y2)/2

So, if we substitute, we can find:

(-2+0)/2 ; (-1+9)/2

This gives us -2/2 and 8/2, which is:

(-1, 4)

Hope this helps!

What is the distance between points (5, 1) and (2, -3)?

Answers

Answer:

5

Step-by-step explanation:

The distance between two points [tex]P[/tex] and [tex]Q[/tex] is  [tex]d = \sqrt{\sum_{i=1}^{n} \left(q_{i} - p_{i}\right)^{2}}[/tex] ([tex]n[/tex] s the number of coordinates of each of the two points, [tex]p_i[/tex] , [tex]i=1..n[/tex] and [tex]q_i,i=1..n[/tex]

are the coordinates of the first and the second points respectively).

Thus, [tex]d = \sqrt{\left(2 - 5\right)^{2} + \left(-3 - 1\right)^{2}}=5.[/tex]

Volume of pyramids cones and spheres

Answers

Answer:

48 cm³

Step-by-step explanation:

Volume = (1/3) * base_area * height

1/3 * 4 * 4 * 9 =

48 cm³

what is 2x-45y=22 when y=21

Answers

answer:

483.5

step by step explanation:

2x-45y=22

2x-45(21)=22

2x-945=22

2x =22+945

2x=967

x=483.5

Complete the table for y=1/2x-3

Answers

Tables are created by substitute a set of input values into the function to create outputs. The required table is as shown below

x | y

0   -3

1   -2.5

2   -2

Tables and values

Tables are created by substitute a set of input values into the function to create outputs

Using x = 0, 1 and 2 as the input values

Given the function

y = 1/2x - 3

If x = 0

y = 1/2(0) - 3

y = -3

If x = 1

y = 1/2(1) - 3

y = -2.5

If x = 2

y = 1/2(2) - 3

y = -2

Hence the required table is as shown below

x | y

0   -3

1   -2.5

2   -2

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(Refer to the attached image)​

Answers

Explanation:

Provided 2 length sides and one angle also need to find one missing side.

So, use cosine rule:

a² = b² + c² - 2bc cos(A)

Part 1

c² = 9² + 11² - 2(11)(9) cos(57)

c² = 94.16147

c = √94.16147 = 9.70 cm

Part 2

d² = 5² + 7² - 2(5)(7) cos(48)

d² = 27.16

d = √27.16 = 5.21

Part 3

5² = 7² + 9² - 2(7)(9) cos(H)

-126cos(H) = 25 - 49 - 81

cos(H) = -105/-126

cos(H) = 5/6

H = cos⁻¹(5/6) = 33.56°

Part 4

8² = 4² + 7² - 2(4)(7) cos(J)

-56cos(J) = 64 - 16 - 49

cos(J) = -1/-56

J = cos⁻¹(1/56) = 88.98°

Passcode: 3142

I don’t know how to do this please help

Answers

Answer:

  84 cm²

Step-by-step explanation:

The figure has a uniform horizontal cross section, so its area is the product of that cross section length and its vertical dimension.

__

  A = bh

  A = (6 cm)(14 cm) = 84 cm²

The area of the shape is 84 square centimeters.

_____

Additional comment

You could decompose the figure into a rectangle with base 6 and height 8, and a parallelogram with base 6 and height 14-8=6. The area formula is the same for each: A = bh, so the area of the composite figure is ...

  A = 6×8 +6×(14 -8)

  = 6×(8 +(14 -8))

  = 6×14 . . . . same as above.

Which graph can be used to find the solution(s) to x2 – 4x + 4 = 2x + 1 + x2?

Answers

The solution to the equation x² – 4x + 4 = 2x + 1 + x² is x = 2.5 and the graph is shown in the picture.

What is a function?

It is defined as a special type of relationship, and they have a predefined domain and range according to the function every value in the domain is related to exactly one value in the range.

We have an equation:

x² – 4x + 4 = 2x + 1 + x²

After solving:

-4x + 4 = 2x + 1

6x = 3

x = 1/2 = 0.5

Thus, the solution to the equation x² – 4x + 4 = 2x + 1 + x² is x = 2.5 and the graph is shown in the picture.

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simplify (x^3+2x-3)-(x^2-2x+4)​

Answers

Answer:

x³ - ((x+1)(x+1))

Step-by-step explanation:

x³ + 2x -3 - x² - 2x + 4

x³ - x² + 1

x³ - ((x+1)(x+1))

Answer:

x^3−x^2+4x−7

Step-by-step explanation:

Hope this helps! Have a great day!!

help me please :)
ytfrtrghjhgfdsfghjyutredfghjytredsfg

Answers

Answer:

what ya need man I can help but give me a question

Which intervals show f(x) decreasing?

Answers

Oh nah that’s why I’m saying that you didn’t mean to me like that too but I just got a message saying it was okay but I’m just okay I just woke up him and I went

Jessie invests $33 in the stock market. Over the 3 years she has this invested she gets an average return of 7,8%. How much will her investment be worth after the 3 years?

Answers

Answer:

it would end up being about $40.73

Step-by-step explanation:

multiply 0.078 by 3 then multiply that by 33

Answer:

hope you can understand

find the coordinate plane that represents the solution of this system y > -x - 1 y + 4 ≤ x

Answers

Answer:

The graph will open to the right and will be mostly in quadrant 1

Step-by-step explanation:

0. on a saturday evening in chicago, 34% of the people go out to dinner, 18% go out to
see a movie, 13% go out to a party, and 35% stay home. if five people are randomly
selected on monday morning, what is the probability that all but one went out saturday
night?
a) 0.048
b) 0.116
c) 0.181
d) 0.312

Answers

Answer
d. 0.312
Steps taken

Can the sides of a triangle have lengths 2, 8, and 19?

Answers

Answer:

No

Step-by-step explanation:

NO...... any two sides added together must be GREATER THAN the third side .... 2 + 8 is NOT greater than 19

Solve 4 x 5/6 Change to a mixed number and reduce.

Answers

Answer:

10/3 or 3.333333

Step-by-step explanation:

-   4 x 5/6 is 3 1/3

-   3 1/3 is a mixed number

- 3 1/3 reduced is 10/3

Hi, so I was wondering if anyone knows the surface area of a cylinder if the diameter is 7.5? Thank you so much! :)

Answers

Answer:

206.17

Key(s):

[tex]A = 2\pi \frac{d}{2} h + 2\pi \left(\frac{d}{2}\right)^2[/tex]

Substitute d for the actual diameter, 7.5, and h for the height, which is 5.

Step-by-step explanation:

[tex]A = 2\cdot\pi \cdot\frac{7.5}{2} \cdot5 + 2\cdot\pi \cdot\left(\frac{7.5}{2}\right)^2[/tex] ≈ 206.17(2 DP)

00B0J0DD:
TIME REMAINING
57:39
The head of the math department compared the scores of students in two classes on the Chapter 2 test. He found that
the mean score of both classes was the same. He also found that there was greater variability in the scores of Ms.
Biren's students than in the scores of Mr. Hayes's students. Which quality of the data sets would lead the department*
head to that conclusion?
The median score i Ms. Biren's class is greater than the median score in Mr. Hayes's class.
The
median score in Ms. Biren's class is less than the median score in Mr. Hayes's class.
The range of scores in Ms. Biren's class is greater than the range of scores in Mr. Hayes's class.
The range of scores in Ms. Biren's class is
less than the range of scores in Mr. Hayes's class. The median score

Answers

Answer: B.

Explanation and reasoning:

Solve this please-
Thanks!!!

Answers

Answer:

130 m²

Step-by-step explanation:

Area of a parallelogram is given by the formula :

A = bh (b is the base length and h is the perpendicular height)

Now we simply substitute values given in diagram to find our answer:

A = bh

A = (13)(10)

A = 130

Units will be m² as this is area

Hope this helped and have a good day

Write the equation of the trigonometric graph.

Answers

Answer:

[tex]f(x)= \sin(6x)+3[/tex]

Step-by-step explanation:

The parent function of this graph is:  y = sin(x)

The sine function is periodic, meaning it repeats forever.

Standard form of a sine function:

[tex]f(x) = \sf A \sin (B(x + C)) + D[/tex]

A = amplitude (height from the mid-line to the peak)2π/B = period (horizontal distance between consecutive peaks)C = phase shift (horizontal shift - positive is to the left)D = vertical shift

The parent function y = sin(x) has the following:

Amplitude (A) = 1Period = 2πPhase shift (C) = 0Vertical shift (D) = 0Mid-line:  y = 0

From inspection of the given graph:

Amplitude (A) = 1[tex]\sf Period=\dfrac{\pi}{12}-\dfrac{-\pi}{4}=\dfrac{\pi}{3}[/tex]Phase shift (C) = 0Vertical shift (D) = +3  (as mid-line is y = 3)

[tex]\sf If\:Period=\dfrac{\pi}{3} \implies \dfrac{2 \pi}{B}=\dfrac{\pi}{3}\implies B=6[/tex]

Substituting the values into the standard form:

[tex]\implies f(x) =1 \sin (6(x + 0)) + 3[/tex]

[tex]\implies f(x) = \sin (6x) + 3[/tex]

Therefore, the equation of the given trigonometric graph is:

[tex]f(x)= \sin(6x)+3[/tex]

Answer(s):

[tex]\displaystyle y = cos\:(6x - \frac{\pi}{2}) + 3 \\ y = -sin\:(6x \pm \pi) + 3 \\ y = sin\:6x + 3[/tex]

Step-by-step explanation:

[tex]\displaystyle y = Acos(Bx - C) + D \\ \\ Vertical\:Shift \hookrightarrow D \\ Horisontal\:[Phase]\:Shift \hookrightarrow \frac{C}{B} \\ Wavelength\:[Period] \hookrightarrow \frac{2}{B}\pi \\ Amplitude \hookrightarrow |A| \\ \\ Vertical\:Shift \hookrightarrow 3 \\ Horisontal\:[Phase]\:Shift \hookrightarrow \frac{C}{B} \hookrightarrow \boxed{\frac{\pi}{12}} \hookrightarrow \frac{\frac{\pi}{2}}{6} \\ Wavelength\:[Period] \hookrightarrow \frac{2}{B}\pi \hookrightarrow \boxed{\frac{\pi}{3}} \hookrightarrow \frac{2}{6}\pi \\ Amplitude \hookrightarrow 1[/tex]

OR

[tex]\displaystyle y = Asin(Bx - C) + D \\ \\ Vertical\:Shift \hookrightarrow D \\ Horisontal\:[Phase]\:Shift \hookrightarrow \frac{C}{B} \\ Wavelength\:[Period] \hookrightarrow \frac{2}{B}\pi \\ Amplitude \hookrightarrow |A| \\ \\ Vertical\:Shift \hookrightarrow 0 \\ Horisontal\:[Phase]\:Shift \hookrightarrow 0 \\ Wavelength\:[Period] \hookrightarrow \frac{2}{B}\pi \hookrightarrow \boxed{\frac{\pi}{3}} \hookrightarrow \frac{2}{6}\pi \\ Amplitude \hookrightarrow 1[/tex]

You will need the above information to help you interpret the graph. First off, keep in mind that although this looks EXACTLY like the sine graph, if you plan on writing your equation as a function of cosine, then there WILL be a horisontal shift, meaning that a C-term will be involved. As you can see, the photograph on the right displays the trigonometric graph of [tex]\displaystyle y = cos\:6x + 3,[/tex]in which you need to replase "sine" with "cosine", then figure out the appropriate C-term that will make the graph horisontally shift and map onto the cosine graph [photograph on the left], accourding to the horisontal shift formula above. Also keep in mind that the −C gives you the OPPOCITE TERMS OF WHAT THEY REALLY ARE, so you must be careful with your calculations. So, between the two photographs, we can tell that the cosine graph [photograph on the right] is shifted [tex]\displaystyle \frac{\pi}{12}\:unit[/tex]to the left, which means that in order to match the sine graph [photograph on the left], we need to shift the graph FORWARD [tex]\displaystyle \frac{\pi}{12}\:unit,[/tex]which means the C-term will be positive, and by perfourming your calculations, you will arrive at [tex]\displaystyle \boxed{\frac{\pi}{12}} = \frac{\frac{\pi}{2}}{6}.[/tex]So, the cosine graph of the sine graph, accourding to the horisontal shift, is [tex]\displaystyle y = cos\:(6x - \frac{\pi}{2}) + 3.[/tex]Now, with all that being said, in this case, sinse you ONLY have a graph to wourk with, you MUST figure the period out by using wavelengths. So, looking at where the graph WILL hit [tex]\displaystyle [-\frac{5}{12}\pi, 2],[/tex]from there to [tex]\displaystyle [-\frac{\pi}{12}, 2],[/tex]they are obviously [tex]\displaystyle \frac{\pi}{3}\:unit[/tex]apart, telling you that the period of the graph is [tex]\displaystyle \frac{\pi}{3}.[/tex]Now, the amplitude is obvious to figure out because it is the A-term, but of cource, if you want to be certain it is the amplitude, look at the graph to see how low and high each crest extends beyond the midline. The midline is the centre of your graph, also known as the vertical shift, which in this case the centre is at [tex]\displaystyle y = 3,[/tex]in which each crest is extended one unit beyond the midline, hence, your amplitude. So, no matter how far the graph shifts vertically, the midline will ALWAYS follow.

I am delighted to assist you at any time.

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