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

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Question 930946: The 15th and 21st terms of an arithmetic sequence are -67 and -97, respectively. What is the 30th term?

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Question 930946: The 15th and 21st terms of an arithmetic sequence are -67 and -97, respectively. What is the 30th term?

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Question 931476: find the first term in a geometric sequence which is such that the sum of the 1st and 3rd term is 50 and the sum of 2nd and 4th term is 150
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Question 931507: 1/3, 8/3, 27/3, 64/3, 125/3 identify the sequence
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Question 932491: Given that A 5 = 46 and A7 = 60 are the 5th and 7th terms in a arithmetic sequence find
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Question 931653: please help me find the following sum: 109, n=37, n thank you
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Question 930941: Find the indicated term of the arithmetic sequence: 25th term: 9, 2, -5, -12...
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Question 928429: next two terms of sequence 1,6,20,56
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Question 884187: Prove there is no largest real number in ~R where ~R is the complement of R the real number set.

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Question 932597: Given that a is an arithmetic sequence, a5=2 and a13=-30 what is a62?
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Question 931537: Solve 1 power 4/ (1 x 3) + 2 power 4 /(3 x 5) +3 power 4/(5 x 7)………………n power 4/(2n-1)(2n+1)




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Question 926701: rewrite the sum using summation notation:
1, -2, 3, -4, 5, -6, 7, -8

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Question 932721: what is the sum of the integers from -10 to 50?
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Question 932882: Hello, I need help with the following question:
Use the properties of logarithms to rewrite the expression as a single logarithm.
3 loga(2-2) loga(3)
The a's are subscript

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Question 932933: if 25 is the arithmetic mean between x and 46 then the value of x is ?
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Question 932968: What is the 84th term in the sequence -3,3,5,-5,-3...? It doesn't look like an arithmetic sequence so we are not sure how to tackle it.
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Question 933070: first term a, common difference d
the sum of the first 200 terms is 4 times the sum of the first 100 terms
-find d in terms of a
-find the 100th term in terms of a

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Question 933253: In a well known story the inventor of the game of chess was asked by his well pleased King what reward he desired. "Oh, not much, your majesty", the inventor responded, "just place a grain of rice on the first square of the board, 2 on the next, 4 on the next, and so on, twice as many on each square as on the preceding one. I will give this rice to the poor." (For the uninitiated, a chess board has 64 squares.) The king thought this a modest request indeed and ordered the rice to be delivered.
Let f(n) denote the number of rice grains placed on the first n squares of the board. So clearly, f(1)=1, f(2) = 1+2 = 3, f(3)= 1+ 2 + 4 =7, and so on.
Part I. Ponder the structure of this summation and then enter an algebraic expression that defines
f(n) = ? as a function of n.
Part II. Supposing that there are 25,000 grains of rice in a pound, 2000 pounds in a ton, and 6 billion people on earth, the inventor's reward would work out to approximately X tons of rice for every person on the planet. Clearly, all the rice in the kingdom would not be enough to begin to fill that request. The story has a sad ending: feeling duped, the king caused the inventor of chess to be beheaded. What is the X value?
Im stumbled, help would be appreciated.




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Question 933251: For the sequence 1/3, 1/3^2, 1/3^3, 1/3^4, 1/3^5,..., find its fifth partial sum and its sixth partial sum.
Help would be appreciated, thanks!

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Question 933274: What is Third Number among Following List ?
06, 57, 93

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Question 933249: For the sequence a sub n = 7/3^n, find its fifth partial sum and its nth partial sum.
Help would truly be appreciated!

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Question 933368: An = -3, 2,7,12,17,….
a- Determine a138
b- Determine the first 40 terms of an

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Question 933337: For each sequence, find a closed formula for the general term, a sub n.
1. 53,477,4293,38637,347733,... a sub n =
2. 2,5,10,17,26,...a sub n =
3. -2,-8,-18,-32,-50,...a sub n =
Help would truly be appreciated!

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Question 933389: The ratio of two numbers is 9 to 5 the sum is 42

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Question 933338: In a well known story the inventor of the game of chess was asked by his well pleased King what reward he desired. "Oh, not much, your majesty", the inventor responded, "just place a grain of rice on the first square of the board, 2 on the next, 4 on the next, and so on, twice as many on each square as on the preceding one. I will give this rice to the poor." (For the uninitiated, a chess board has 64 squares.) The king thought this a modest request indeed and ordered the rice to be delivered.
Let f(n) denote the number of rice grains placed on the first n squares of the board. So clearly, f(1)=1, f(2) = 1+2 = 3, f(3)= 1+ 2 + 4 =7, and so on.

PART I. Ponder the structure of this summation and then enter an algebraic expression that defines
f(n) = as a function of n.
PART II. Supposing that there are 25,000 grains of rice in a pound, 2000 pounds in a ton, and 6 billion people on earth, the inventor's reward would work out to approximately X tons of rice for every person on the planet. Clearly, all the rice in the kingdom would not be enough to begin to fill that request. The story has a sad ending: feeling duped, the king caused the inventor of chess to be beheaded. What is the X value?
Hint: Note the relationship between the number of grains on each square, and the number of grains on the preceding squares combined.

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Question 933557: 4th term Of an arithmetic sequence is 17. Sum of first 20 terms is 990. Find first term and common difference.
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Question 933534: The first difference of a sequence is 3, 9, 15, 21,... The sum of the first two terms of the original sequence is 21. Find the first three terms of the original sequence.
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Question 933241: For each sequence, find a closed formula for the general term, a sub n.
1. 53,477,4293,38637,347733,... a sub n =
2. 2,5,10,17,26,...a sub n =
3. -2,-8,-18,-32,-50,...a sub n =
Help would truly be appreciated!

Click here to see answer by Edwin McCravy(20056) About Me 

Question 933569: we have to arrange chairs for the audience a in the first row we can place 20 chairs in the next 22 chairs 2 chairs can be added to each row than the previous one we have to arrange 50 so how many chairs are needed WE HAVE TO USE AP FORMULA
(arithmetic progression)
so how many chairs will be in the 25th row?
with thousand how many perfect rows can you make?
how many chairs will be in the last row?
what are the difference in the number of chairs for arranging 25 rows and 50 rows?
in which row 50 chairs will exist?
will you be able to make perfect rows with thousand chairs? if not how many chairs are needed to make the row perfect?
if you need to make 2 more rows how more chairs are needed?

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Question 933617: The nth term of a sequence is denoted by 3n(2^n-1).find the sum of the first 5 terms
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Question 933333: If a,b,c,d are in H.P., prove that ab+bc+cd = 3ad
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Question 933723: given the following patterns 3,10,17,24 what is the 48th term in this pattern
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Question 933079: 2 5 7 11 14 19 23 29 ?

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Question 932868: in an arithmetic series, the second to last term is three times the fifth term, the sum of the first eight terms equals 136, and the fourteenth term equals the twentieth minus the second term. Determine how many terms are in the arithmetic series.
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Question 932735: Sequence : 7,9,11,13....
Find sigma notation for the sum of the first twenty terms

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Question 933870: Find the fifth, ninth and hundredth term of the sequence.
-19, -22, -25, -28,
A(n) = -19 + (n - 1)(-3)
I can't get this question correct, apparently. D:

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Question 933872: Question 1000÷1/2=?

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Question 933872: Question 1000÷1/2=?

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Question 933335: If a,b,c, are in G.P and a^x=b^y=c^z the x,y,z are in
1)H.P
2)G.P
3)A.P

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Question 933871: Find the sixth, tenth, and sixtieth terms of the sequence.
A(n) = -1 + (n - 1)(-10)

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Question 933943: in the sequence, 3ˏ7/3ˏ5/3ˏ… what term is −17
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Question 933943: in the sequence, 3ˏ7/3ˏ5/3ˏ… what term is −17
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Question 931204: PLEASE GIVE THE SOLUTION AS SOON AS POSSIBLE. log(1+px+qx.x)=(X+Y)x-(X.X+Y.Y)x.x/2+(X.X.X+Y.Y.Y)x.x.x/3...........
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Question 932628: The three terms 7x+1, 9x+7, and 3x-4 (not necessarily in order) are 3 consecutive terms of an arithmetic sequence. Find the largest possible value of the common difference of such an arithmetic sequence.
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Question 933858: a,b,c are in AP if 1,4 19 are subtracted from then it is in GP: Find a,b,c
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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, 1216..1260, 1261..1305, 1306..1350, 1351..1395, 1396..1440, 1441..1485, 1486..1530, 1531..1575, 1576..1620, 1621..1665, 1666..1710, 1711..1755, 1756..1800, 1801..1845, 1846..1890, 1891..1935, 1936..1980, 1981..2025, 2026..2070, 2071..2115, 2116..2160, 2161..2205, 2206..2250, 2251..2295, 2296..2340, 2341..2385, 2386..2430, 2431..2475, 2476..2520, 2521..2565, 2566..2610, 2611..2655, 2656..2700, 2701..2745, 2746..2790, 2791..2835, 2836..2880, 2881..2925, 2926..2970, 2971..3015, 3016..3060, 3061..3105, 3106..3150, 3151..3195, 3196..3240, 3241..3285, 3286..3330, 3331..3375, 3376..3420, 3421..3465, 3466..3510, 3511..3555, 3556..3600, 3601..3645, 3646..3690, 3691..3735, 3736..3780, 3781..3825, 3826..3870, 3871..3915, 3916..3960, 3961..4005, 4006..4050, 4051..4095, 4096..4140, 4141..4185, 4186..4230, 4231..4275, 4276..4320, 4321..4365, 4366..4410, 4411..4455, 4456..4500, 4501..4545, 4546..4590, 4591..4635, 4636..4680, 4681..4725, 4726..4770, 4771..4815, 4816..4860, 4861..4905, 4906..4950, 4951..4995, 4996..5040, 5041..5085, 5086..5130, 5131..5175, 5176..5220, 5221..5265, 5266..5310, 5311..5355, 5356..5400, 5401..5445, 5446..5490, 5491..5535, 5536..5580, 5581..5625, 5626..5670, 5671..5715, 5716..5760, 5761..5805, 5806..5850, 5851..5895, 5896..5940, 5941..5985, 5986..6030, 6031..6075, 6076..6120, 6121..6165, 6166..6210, 6211..6255, 6256..6300, 6301..6345, 6346..6390, 6391..6435, 6436..6480, 6481..6525, 6526..6570, 6571..6615, 6616..6660, 6661..6705, 6706..6750, 6751..6795, 6796..6840, 6841..6885, 6886..6930, 6931..6975, 6976..7020, 7021..7065, 7066..7110, 7111..7155, 7156..7200, 7201..7245, 7246..7290, 7291..7335, 7336..7380, 7381..7425, 7426..7470, 7471..7515, 7516..7560, 7561..7605, 7606..7650, 7651..7695, 7696..7740, 7741..7785, 7786..7830, 7831..7875, 7876..7920, 7921..7965, 7966..8010, 8011..8055, 8056..8100, 8101..8145, 8146..8190, 8191..8235, 8236..8280, 8281..8325, 8326..8370, 8371..8415, 8416..8460, 8461..8505, 8506..8550, 8551..8595, 8596..8640, 8641..8685, 8686..8730, 8731..8775, 8776..8820, 8821..8865, 8866..8910, 8911..8955, 8956..9000, 9001..9045, 9046..9090, 9091..9135, 9136..9180, 9181..9225, 9226..9270, 9271..9315, 9316..9360, 9361..9405, 9406..9450, 9451..9495, 9496..9540, 9541..9585, 9586..9630, 9631..9675, 9676..9720, 9721..9765, 9766..9810, 9811..9855, 9856..9900, 9901..9945, 9946..9990, 9991..10035, 10036..10080, 10081..10125, 10126..10170, 10171..10215, 10216..10260, 10261..10305, 10306..10350, 10351..10395, 10396..10440, 10441..10485, 10486..10530, 10531..10575, 10576..10620, 10621..10665, 10666..10710, 10711..10755, 10756..10800, 10801..10845, 10846..10890, 10891..10935, 10936..10980, 10981..11025, 11026..11070, 11071..11115, 11116..11160, 11161..11205, 11206..11250, 11251..11295, 11296..11340, 11341..11385, 11386..11430, 11431..11475, 11476..11520, 11521..11565, 11566..11610, 11611..11655, 11656..11700, 11701..11745, 11746..11790