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

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Question 1042120: please help me solve this:
find the nth term of the following harmonic series
1/7, 1/11, 1/15, ... n=6
Click here to see answer by stanbon(75887)

Question 1042111: 1. In geometric sequence,the 2nd term is 2 and the 6th term is 2/81.Find the common ratio.
2.The sum of the first 5 terms of a geometric sequence is 93.If the 10th term is 3/2,find the common ratio and the 4th term of the sequence
Click here to see answer by KMST(5328)

Question 1042363: The sum of first three terms of a finite geometric series is -(7/10) and their product is -(1/125). [Hint: Use a/r, a, and ar to represent the first three terms, respectively.] The three numbers are _____, _____, and _____.
Click here to see answer by stanbon(75887)

Question 1042356: Sum i1-7(i-1)^3?
Sum i0-100[1/k-1/k+1]?
Sum i2-3(xi+2)/xi?
Sum i1-6(3i-2)?
Sum i2-6(xi+1)^2?

Click here to see answer by Alan3354(69443)

Question 1042360: Suppose you start an annuity where you invest $2,000 at the beginning of each year and 4% interest is paid at the end of the year. What is the value of the annuity at the end of 5 years, rounded to the nearest dollar? It is $

Click here to see answer by robertb(5830)

Question 1042444: Please help me to solve this question ,Set A consists of positive odd numbers less than 100,set B consists of positive even numbers less than 5 and set C consists of product of all the numbers in set A and set B.what is the number of different numbers possible in set C.
Click here to see answer by Fombitz(32388)

Question 1042506: find the fractional notation for 0.1919191919
Click here to see answer by stanbon(75887)

Question 1042555: What is the next term in the sequence 3/2,1,2/3,4/9, ___?
thank you
Click here to see answer by Edwin McCravy(20056)

Question 1042593: (1-1/3) (1-1/4) (1-1/5)....(1-1/n)=?
Click here to see answer by Edwin McCravy(20056)

Question 1042871: Please can you get me the two following numbers in this serie on the place of the x and y?
1, 4, 12, 40, 112, x, y,
Click here to see answer by ikleyn(52788)

Question 1042999: How do i write an equation for the nth term of the arithmetic sequence.
3,6,9,12,...
Click here to see answer by ikleyn(52788)

Question 1043002: How do i write an equation for the nth term of this arithmetic sequence.
2,13,24,35,...
Click here to see answer by ikleyn(52788)

Question 1043001: How do i write an equation for the nth term of this arithmetic sequence.
7,0,-7,-14,...
Click here to see answer by ikleyn(52788)

Question 1043122: Find the Sn of the given artithmetic series.
a1=-100, d=-1, n=21
Click here to see answer by ikleyn(52788)

Question 1043124: table
Less than 25 Years 25�35 Years Above 35 Years Total
Less than 9 21 32 76 129
Between 9 and 11 49 52 46 147
Above 11 69 44 40 153
Total 139 128 162 429

the probability that a person older
than 35 years has a hemoglobin
level less than 9
the probability that a person
younger than 25 years has a
hemoglobin level above 11
the probability that a person in the
25�35 age group has a hemoglobin
level less than 9
the probability that a person older
than 35 years has a hemoglobin
level between 9 and 11

Click here to see answer by ikleyn(52788)

Question 1043123: Next number in series 1 2 8 48 384
Click here to see answer by ikleyn(52788)

Question 1043123: Next number in series 1 2 8 48 384
Click here to see answer by robertb(5830)

Question 1043125: Next number in series 100 96 104 88 120 56
Click here to see answer by jim_thompson5910(35256)

Question 1043125: Next number in series 100 96 104 88 120 56
Click here to see answer by ikleyn(52788)

Question 1043382: A+b=8,c-d=6,a+c=13,b+d=8. What are values of a,b,c and d
Click here to see answer by solver91311(24713)

Question 1043382: A+b=8,c-d=6,a+c=13,b+d=8. What are values of a,b,c and d
Click here to see answer by ikleyn(52788)

Question 1043393: 799,761,685,?,419,229
Click here to see answer by solver91311(24713)

Question 1043390: The interior angles of a convex polygon form arithmetic progression with common difference 4� .Determine the sides of the polygon if its largest interior angle is 172�.
Click here to see answer by KMST(5328)

Question 1043415: Find a number x which, when added to each of the numbers 21, 27, and 29 in this order, produces three numbers which are in a geometric progression.
Click here to see answer by rothauserc(4718)

Question 1043444: The nth term of a series is 1/2(2n-1). Write down the (n+1)th term.
Click here to see answer by ikleyn(52788)

Question 1043481: In the geometric sequence, the common ratio is -5 and the sum of the first three terms is 147. What are the first three terms?
Click here to see answer by josgarithmetic(39618)

Question 1043503: What are the two geometric means between 160 and 20
Click here to see answer by Boreal(15235)

Question 1043578: The first 3 terms of a G.P are x,x+2,x+3, then value of x is?

Click here to see answer by josgarithmetic(39618)

Question 1043621: What is the value of the fourth term in a geometric sequence for which a1=15 and r=1/3?
Click here to see answer by ikleyn(52788)

Question 1043667: The next term of sequence 1,8,27,64.....is?
Click here to see answer by josmiceli(19441)

Question 1043531: What is the next number in the series: 64, 35, 32, 29, 16? Please help!
Click here to see answer by Edwin McCravy(20056)

Question 1043664: If 4,x+4 and 5-2x are the first 3 terms of an infinite GP. Whose sum is finite the value of this finite sum is?

Click here to see answer by josgarithmetic(39618)

Question 1043665: Find the 20th term of a HP.of which the first two terms are 2/39 and 2/37
Click here to see answer by ikleyn(52788)

Question 1043665: Find the 20th term of a HP.of which the first two terms are 2/39 and 2/37
Click here to see answer by robertb(5830)

Question 1043775:
? + ? = 8 + + ? - ? = 6 ∥ ∥ 13 8

Click here to see answer by Edwin McCravy(20056)

Question 1043785: in a class of 19 mathematicians and 13 chemists two learners are randomly selected one after the other what is the probability that the selected learners are mathematicians?
help me this one pliz.
Click here to see answer by Alan3354(69443)

Question 1043786: 13 pupils have to be divided into three groups of 4,5 and 4..in how many ways can this be dan?
Click here to see answer by Edwin McCravy(20056)

Question 1043856: What is the sum of all those natural numbers which when added to 29 gives a two digit square number?
Click here to see answer by josgarithmetic(39618)

Question 1043856: What is the sum of all those natural numbers which when added to 29 gives a two digit square number?
Click here to see answer by ikleyn(52788)

Question 1043793: x+y +(x^2+xy+y^2)+(x^3+x^2y+xy^2+y^3)+...to infinite terms

Click here to see answer by ikleyn(52788)

Question 1043483: pls answer it - the first term of arithmetic mean is 1 and the sum of first 9 terms is equal to369 the first and ninth term of gp coincide with first and ninth term of ap find seventh term of gp
Click here to see answer by KMST(5328)

Question 1043956: What is the nth term of arithmetic sequence 7,9,11,13,15,17,..?
Click here to see answer by solver91311(24713)

Question 1044033: Prove by mathematical induction that
the statements below holds true for every
integer n belongs to N.
1. 1/2 - 1/4 - 1/8 ... - 1/2n =1/2^n
2. 1/1.2 + 1/3.4 + 1/4.5 + ... + 1/n(n + 1) = n/n + 1
Click here to see answer by ikleyn(52788)

Question 1044046: Prove by mathematical induction that
the statement below holds true for every
integer n belongs to N.
1/2 - 1/4 - 1/8 ... - 1/2n =1/2^n
Click here to see answer by ikleyn(52788)

Question 1044272: All terms of an arithmetic sequence are integers. The first term is 535, the last
term is 567, and the sequence has n terms. What is the sum of all possible values
of n?
Answer: 69 (How)?
Click here to see answer by Fombitz(32388)

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