Questions on Algebra: Sequences of numbers, series and how to sum them answered by real tutors!

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Tutors Answer Your Questions about Sequences-and-series (FREE)


Question 42187: -64, 32,-16, 8,-4
is this sequence geometric, arithmetic, or neither

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Question 42189: 1/12, 2/13, 3/14, 4/15...
is this sequence geometric, arithmetic, or neither

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Question 42475: what are the rules governing the operation on si
gned numbers?

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Question 42557: How many four-digit numerical codes can be created if no digit may be repeated?
Thanks

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Question 42555: Find the sum of the infinite geometric series: 1 + 3/5 + 9/25 + ..., if it exists.
Thanks

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Question 42556: Use the Binomial Theorem to find the sixth term in the expansion of (m+2p)^7.
Thanks

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Question 41753This question is from textbook college algebra
: A.Using the index of a sequence as the domain and the value of the sequence as the range, is a sequence a function?
Include the following in your answer:
b.Which one of the basic functions (linear, quadratic, rational, or exponential) is related to the arithmetic sequence?
c.Which one of the basic functions (linear, quadratic, rational, or exponential) is related to the geometric sequence?
d.Give at least two real-life examples of a sequences or series. One example should be arithmetic, and the second should be geometric. Explain how these examples would affect you personally.
I don't understand this question.Can someone please help this is recking my brain.
This question is from textbook college algebra

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Question 42841: The sequence 2,3,5,6,7,10,... consists opf all natural numbers which are neither perfect squares nor perfect cubes. Find the 75th term of this sequence?
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Question 42912: Determine the sum for the geometric series 1/2 - 1/3 + 2/9 - 4/27 +...
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Question 42910: Determine the sum of the geometric series 27+18+12+8+...
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Question 42939: write the sigma noation for the series sonsisting of positive two-digit intergers ending in 2
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Question 41712: Find the sum of a geometric series for which a1=1, r=2, and n=6.
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Question 42956: determine the sum for the positive two-digit integers that are not divisible by 5
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Question 41710: Find the next two terms of the geometric sequence 6250, 5000, 4000,...
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Question 43315: Write out the first five terms of the sequence given by:
ok HELP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
a_n=n^2-n
first n is a subsc.
a. 0, 2, 6, 12, 20
b. 2, 6, 12, 20, 30
c. 1, 4, 9, 16, 25
d. 0, 3, 8, 15, 24
e. None of the others

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Question 43317: I just don't even know what to say..................help!!!!!!!!!!!!!!!!!
Given the following recursively defined sequence, find the fifth term.
a_1 = -4
a_2 = -4
a(_n+2)= a(_n+1)-4a_n
a. 28
b. 764
c. -20
d. -308
e. None of the others

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Question 43317: I just don't even know what to say..................help!!!!!!!!!!!!!!!!!
Given the following recursively defined sequence, find the fifth term.
a_1 = -4
a_2 = -4
a(_n+2)= a(_n+1)-4a_n
a. 28
b. 764
c. -20
d. -308
e. None of the others

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Question 41707: Find the three arithmetic means between 21 and 13.
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Question 41706: Find the next four terms of the arithmetic sequence 4,10,16,...
Thanks

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Question 41708: Find Sn for the arithmetic series in which a1=an=13, n=7.
Thanks

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Question 41708: Find Sn for the arithmetic series in which a1=an=13, n=7.
Thanks

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Question 43732: a1=135 and an+1=1/3 (an)for n>or=2
The sequence is defined recursively. Write the first four terms.

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Question 43775: find the values of the six trigonometric functions of an angle q in standard position whose terminal side passes through the point (-2, 5).
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Question 44039This question is from textbook
: Please help me solve the following problems. I've tried to solve the problem but I don't it correct.
1) Use the arithmetic sequence of numbers 1, 3, 5, 7, 9,…to find the following:
a)What is d, the difference between any 2 terms?
Answer:
d = 2
Show work in this space.
3-1=2
5-3=2
b)Using the formula for the nth term of an arithmetic sequence, what is 101st term?
Answer:
an = 1 + (n - 1)2

Show work in this space.

c)Using the formula for the sum of an arithmetic series, what is the sum of the first 20 terms?
Answer:
Sum a20 = 400
Show work in this space
Sum an = n[2a1 + (n - 1)d] / 2
Sum a20 = 20[2 + (20 - 1)2] / 2
Sum a20 = 10[2 + (20 - 1)2]
Sum a20 = 10[2 + (19)2]
Sum a20 = 10[2 + 38]
Sum a20 = 10[40]
Sum a20 = 400


d)Using the formula for the sum of an arithmetic series, what is the sum of the first 30 terms?
Answer:

Sum a20 = 900

Show work in this space
Sum an = n[2a1 + (n - 1)d] / 2
Sum a20 = 30[2 + (30 - 1)2] / 2
Sum a20 = 15[2 + (30 - 1)2]
Sum a20 = 15[2 + (29)2]
Sum a20 = 15[2 + 58]
Sum a20 = 15[60]
Sum a20 = 900


e)What observation can you make about these sums of this series (HINT: It would be beneficial to find a few more sums like the sum of the first 2, then the first 3, etc.)? Express your observations as a general formula in "n."
Answer:

N an Sum
1 1
2 3 4
3 5 9
4 7 16
5 9 25
6 11 36
7 13 49
8 15 64
9 17 81
The sum of the nth in the series is the square of n.
This question is from textbook

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Question 44372: I'm having problem soving the following problems. Please help.
2) Use the geometric sequence of numbers 1, 2, 4, 8,…to find the following:
a) What is r, the ratio between 2 consecutive terms?
Answer:
Show work in this space.



b) Using the formula for the nth term of a geometric sequence, what is the 24th term?
Answer:
Show work in this space.



c) Using the formula for the sum of a geometric series, what is the sum of the first 10 terms?
Answer:
Show work in this space



3) Use the geometric sequence of numbers 1, 1/2, 1/4, 1/8,…to find the following:
a) What is r, the ratio between 2 consecutive terms?
Answer:
Show work in this space.



b) Using the formula for the sum of the first n terms of a geometric series, what is the sum of the first 10 terms? Please round your answer to 4 decimals.
Answer:
Show work in this space.


c) Using the formula for the sum of the first n terms of a geometric series, what is the sum of the first 12 terms? Please round your answer to 4 decimals.
Answer:
Show work in this space.



d) What observation can make about these sums? In particular, what number does it appear that the sum will always be smaller than?
Answer:



4) CLASSIC PROBLEM - A traveling salesman (selling shoes) stops at a farm in the Midwest. Before he could knock on the door, he noticed an old truck on fire. He rushed over and pulled a young lady out of the flaming truck. Farmer Brown came out and gratefully thanked the traveling salesman for saving his daughter’s life. Mr. Brown insisted on giving the man an award for his heroism.
So, the salesman said, “If you insist, I do not want much. Get your checkerboard and place one penny on the first square. Then place two pennies on the next square. Then place four pennies on the third square. Continue this until all 64 squares are covered with pennies.” As he’d been saving pennies for over 25 years, Mr. Brown did not consider this much of an award, but soon realized he made a miscalculation on the amount of money involved.
a) How much money expressed in dollars would Mr. Brown have to put on the 32nd square?
Answer:
Show work in this space

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Question 44629: I've got this problem (see below). I've worked through problems 1b - 1d, but I am stuck with how to answer 1e. Can someone help?
Thanks A Bunch!
1) Use the arithmetic sequence of numbers 1, 3, 5, 7, 9,…to find the following:
a) What is d, the difference between any 2 terms?
Answer: d = 2
Show work in this space.
The difference between any two terms = (n+1 ) th term - (n) th term
So, the difference d = 3-1 = 5-3 = 7-5 = 2
Answer d = 2


b) Using the formula for the nth term of an arithmetic sequence, what is 101st term?

Answer: nth term = 201


Show work in this space.
Given a = first term = 1
n = 101
d = 2
putting above values in formula 1
nth term = 1 + (101-1) * 2
= 1 + 200 = 201
So, nth term = 201

c) Using the formula for the sum of an arithmetic series, what is the sum of the first 20 terms?
Answer: 400
Show work in this space
n = 20
a = first term = 1
So, sum = 20 / 2 (2 * 1 + 19 * 2)
= 10 * (40)
sum = 400



d) Using the formula for the sum of an arithmetic series, what is the sum of the first 30 terms? =n/2(a +(n-1)d)…………..(1)
Answer: 900
Show work in this space
given that n = 30
a = first term =1
= 30 / 2 (2 * 1 + 29 * 2)
=15 * (60)
= 900

e) What observation can you make about these sums of this series (HINT: It would be beneficial to find a few more sums like the sum of the first 2, then the first 3, etc.)? Express your observations as a general formula in "n."
Answer:

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Question 44597: A traveling salesman (selling shoes) stops at a farm in the Midwest. Before he could knock on the door, he noticed an old truck on fire. He rushed over and pulled a young lady out of the flaming truck. Farmer Brown came out and gratefully thanked the traveling salesman for saving his daughter’s life. Mr. Brown insisted on giving the man an award for his heroism.
So, the salesman said, “If you insist, I do not want much. Get your checkerboard and place one penny on the first square. Then place two pennies on the next square. Then place four pennies on the third square. Continue this until all 64 squares are covered with pennies.” As he’d been saving pennies for over 25 years, Mr. Brown did not consider this much of an award, but soon realized he made a miscalculation on the amount of money involved.
a) How much money expressed in dollars would Mr. Brown have to put on the 32nd square?
Answer:

Show work in this space



b) How much money expressed in dollars would the traveling salesman receive in total if the checkerboard only had 32 squares?
Answer:
Show work in this space



c) Calculate the amount of money necessary to fill the whole checkerboard (64 squares). How money expressed in dollars would the farmer need to give the salesman?
Answer:
Show work in this space

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Question 44658: PLEASE, PLEASE HELP ME!!!!!!!!!!!
Using the index of a sequence as the domain and the value of the sequence as the range, is a sequence a function?
Include the following in your answer:
Which one of the basic functions (linear, quadratic, rational, or exponential) is related to the arithmetic sequence?
Which one of the basic functions (linear, quadratic, rational, or exponential) is related to the geometric sequence?
Give at least two real-life examples of a sequences or series. One example should be arithmetic, and the second should be geometric. Explain how these examples would affect you personally.

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Question 43773: 11
Tell Whether the series: å (35 - n) is arithmetic, geometric, or neither.
n-1

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Question 45041: the sum of the squares of two consecutive even integers 1252. find the inetegers
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Question 45041: the sum of the squares of two consecutive even integers 1252. find the inetegers
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Question 45574: Consecutive integers. Find three consecutive integers such that the sum of their squares is 77. Please show all work and solution. Thanks.
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Question 45661: Hi,
I could really use some help with this problem:
Find a number such that one half of its square is equal to twice the number plus six.
Thanks in advance,
Louis

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Question 45868: Hi again,
I could use some assistance with this problem:
Prove that if the sum of two numbers is constant, then their product is maximum if the numbers are equal.
Thank you,
Louis

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Question 45922: Hi again,
This type of problem is still giving me some trouble:
The sum of the squares of two numbers is 117. The difference of the squares of the same two numbers is 45. Find the numbers.
Thanks again,
Louis

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Question 46085: Hello,
I could really use help with this problem:
The product of two numbers is 20, and the sum of their reciprocals is 3/5. Find the numbers.
Thank you in advance,
Louis

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Question 46085: Hello,
I could really use help with this problem:
The product of two numbers is 20, and the sum of their reciprocals is 3/5. Find the numbers.
Thank you in advance,
Louis

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Question 46736: Find the first 3 terms and the 15th term of the sequence that has the given nth term:
an = 3n – 2.

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Question 46737: Find the 100th term of a certain arithmetic sequence, given that the 7th term is 16 and the 61st term is 232.
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Question 46786: The given pattern continues. Write down the nth term of the sequence suggested by the pattern.
0,2,6,12,20,...
A) a n=n^2-n
B) a n=2n-2
C) a n=4n-6
D) a n=2^n-1 -1
I have looked but am unable to understand how these patterns work. Please help!
Thanks!

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Question 46789: A pendulum bob swings through an arc 70 inches long on its first swing. Each swing, thereafter, it swings only 89% as far as on the previous swing. What is the length of the arc after 9 swings?
Round your answer to two decimal places, if necessary.
I need to know how to set this problem up please. I get mixed up when trying to set it up and then become completely frustrated! Please help!

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Question 46798: I am unsure of how to work this problem. Can anyone give me some advice?
(x-8)^5
We are supposed to expand the expression using the Binomial Theorem.
Thank you very much.

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Question 46910: Simplify 3x(4x-5xy+2)-2(-6xto the second power+4xy-3x)
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Question 46876This question is from textbook COLLEGE ALGEBRA
: Use the binomial theorem to find (2x + 1) ^4 and write answer in simplified form.This question is from textbook COLLEGE ALGEBRA

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Question 46874This question is from textbook COLLEGE ALGEBRA
: Find the sum of the infinite geometric series:
1 + 1/5 + 1/25 + 1/125 + ...
This question is from textbook COLLEGE ALGEBRA

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Older solutions: 1..45, 46..90, 91..135, 136..180, 181..225, 226..270, 271..315, 316..360, 361..405, 406..450, 451..495, 496..540, 541..585, 586..630, 631..675, 676..720, 721..765, 766..810, 811..855, 856..900, 901..945, 946..990, 991..1035, 1036..1080, 1081..1125, 1126..1170, 1171..1215