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

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

Question 858035: Calculate the sum of 1/3 and 1/5
Click here to see answer by josmiceli(19441)

Question 858046: 2n-1/8=1/2
What is n

Click here to see answer by Seutip(231)

Question 858064: 4th and 7th term of an AP are 9 and 21 respectively. Find the 1st eight terms of the sequence
Click here to see answer by richwmiller(17219)

Question 858285: Find the first term of an A.p if the 5th term is 28 and sum of the first 17th term is Zero
Click here to see answer by mananth(16946)

Question 858287: two arithmetic series are such that their common difference are 9 and 3 respectively. If their first terms are 2 and 5 respectively, find the number of terms of each series that would give a common sum.
Click here to see answer by mananth(16946)

Question 858284: Three consecutive numbers of a G.p are such that there sum is 26 and there product is 216.Find the numbers
Click here to see answer by KMST(5328)

Question 858278: Three consecutive numbers of G.p are such that there sum is 26 and there product is 216. Find the numbers.
Click here to see answer by richwmiller(17219)

Question 130909: Find three numbers in a GP whose sum is 26 and and product is 216
Click here to see answer by richwmiller(17219)

Question 858277: Three consecutive numbers of G.p
Click here to see answer by richwmiller(17219)

Question 858645: The sum of three consecutive terms of an A.P. is 18 and their product is 162.Find the terms.
Click here to see answer by mananth(16946)

Question 858715: Determine if the following sequence is geometric, arithmetic, neither, or not even a sequence.
3,10,17,24,31,�

Click here to see answer by richwmiller(17219)

Question 858970: How would you explain to them the difference between a sequence and series?
How would you explain what algebraic and geometric sequences are and how to tell the difference between them?
Click here to see answer by richwmiller(17219)

Question 858519: What is the explicit formula for 1/2,1,9/8,1,25/32 ?
Click here to see answer by richwmiller(17219)

Question 858999: Kindly help me on this problem..i'm realy confuse regarding the answers provided.thanx
1. 3^2 is to 9 as 9^2 is to _______
2. 30% is to 3/5 as 60% is to ____________
3. 0.25 is to 0.125 as 1.25 is to ________
4. 12.5 is to 1/8 as 20 is to _________
5. 6 is to 15 as 36 is to ________
Click here to see answer by lwsshak3(11628)

Question 858789: Continue the sequence
-11, ,-3, , ,7,
Click here to see answer by richwmiller(17219)

Question 858024: In the sequence which begins 2, 3, 5, 10... each number after the second sum of all the previous numbers in the sequence.
What is the 10th number in the sequence?
Click here to see answer by richwmiller(17219)

Question 859194: Find 'n' for an arithmetic sequence for which Sn= 345, a=12, and d=5.

Click here to see answer by ewatrrr(24785)

Question 859198: Find 'n' for an arithmetic sequence for which Sn=345, a=12, and d=5.
Click here to see answer by ewatrrr(24785)

Question 859549: Given the terms of the geometric sequence 2, 2 , 4, .... Find the tenth term in the sequence and leave the answer in radical form.
Click here to see answer by ewatrrr(24785)

Question 859584: In an arithmetic sequence with the 2nd term 8 and the 6th term 20, find the 100th term?
Click here to see answer by richwmiller(17219)

Question 851813: Mr Nkomo gives his son R50000 on his eighteenth birthday.the money is invested on fixed deposit at 18% per annum compounded monthly. How old will the son be,when he is able to collect one million rand from his investment.
Click here to see answer by richwmiller(17219)

Question 859672: How many three digit numbers can you make using the numbers 1, 3, 5, 7. Each number can only be used one in each three digit number created.
Click here to see answer by jim_thompson5910(35256)

Question 859701: 5(b+4y)+6(b-2y)
Click here to see answer by jim_thompson5910(35256)

Question 859776: Consider two different arithmetic sequences:
3,14,25,36,47,58 ....where numbers increase by 11 and
2,9,16,23,30 .... where numbers increase by 7.
What are the first 10 numbers which appear in both sequences ????
Please help ... thank you!!!

Click here to see answer by Fombitz(32388)

Question 859811: Given two different arithmetic sequences 3,14,25,36 (obviously increasing by 11)
and 2,9,16,23 (obviously increasing by 7). What are the first 10 numbers which appear in both sequences ?
One tutor answered it with a solution that I had already done (the long way) which is simply to "keep adding 11 and 7 until you have 10 terms that match. All of which is true, but isn't there a formula that can be used to solve it a different way?
Click here to see answer by richwmiller(17219)

Question 859879: What is the 12th term in the addition pattern with formula An=6n � 7?
A.59 B.65 C.71 D.72
Click here to see answer by richwmiller(17219)

Question 860047: The first term of an AP is 7, the last term is 77,the sum is 380. Find the common difference in the series?
Click here to see answer by richwmiller(17219)

Question 860167: In a geometric sequence, find the first five terms when An=(2)^n-1, starting with n=1. I would think this is (2)^1-1 which would be (2)^0=0, next would be (2)^2-1 =2, next would be (2)^3-1=4, (2)^4-1=6, and (2)^5-1=8. However this answer of (0,2,4,6,8) is not a choice I have. Can someone help me understand if I am doing something wrong?

Click here to see answer by rothauserc(4718)

Question 860201: limit as n goes to infinity of
Click here to see answer by richwmiller(17219)

Question 860299: y varies jointly as x and z. y=72 when x=3 and z=6. Find y when x=7 and z=4
y=
Click here to see answer by stanbon(75887)

Question 860298: Write an equation that expresses the following relationship: x varies directly as z and inversely as the difference between y and p. Then solve the equation for y.
Write an equation that expresses the given relationship. Use k as the constant of variation.
x=
Click here to see answer by stanbon(75887)

Question 860385: The sum of the first n squares, given by the sum of the terms 1+4+9+...n^2 can be calculated by using the formula n/6(n+1)(2n+1).
What is the value of the 20th term of the series?
Find the sum of the first 25 squares.
Do I just have to put 20 and 25 instead of n? Cos I'm not quite sure what I have to do.
Click here to see answer by richwmiller(17219)

Question 860295: Y varies directly as x and inversely as the square of z. y=24 when x= 12 and z=2. Find y when x=64 and z=4.
y=
Click here to see answer by richwmiller(17219)

Question 860354: Determine 3 distinct and positive numbers a,b,c forming a geometric sequence verifying ac=49 and 7a+6b-c=0
Click here to see answer by richwmiller(17219)

Question 860335: use mathematical induction to prove that +...+
Click here to see answer by KMST(5328)

Question 860618: The sum of the first seven terms of an AP is 98 and the sum of the first twelve terms is 288.Find the sum of the first twenty terms.
Click here to see answer by ewatrrr(24785)

Question 860643: in an arithmetic sequence, what is d if a1 is 13 and a71 is 223
Click here to see answer by ewatrrr(24785)

Question 860614: If the geometric mean of 1/4 and 4 is x+3,find the possible values of x.
Click here to see answer by richwmiller(17219)

Question 860683: find n for the series for which an =138 a1 =-2 and d=7
Click here to see answer by richwmiller(17219)

Question 860678: find the sum of the first eight terms in the series -4+8-16+�
Click here to see answer by richwmiller(17219)

Question 860691: find the common ratio, the first term, and an explicit formula for the nth term. Given a2=3 and a8=192
Click here to see answer by richwmiller(17219)

Question 860692: Given that for an AP seventh term is equal to 43,nth term and 2nd term is equal to 91,find the valves of a,d and n
Click here to see answer by ewatrrr(24785)

Question 860692: Given that for an AP seventh term is equal to 43,nth term and 2nd term is equal to 91,find the valves of a,d and n
Click here to see answer by richwmiller(17219)

Question 860718: find the common difference, the first term, and the recursive formula for the nth term. Given a3=14 and a8=-3.5
Click here to see answer by ewatrrr(24785)

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