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 1011504: f(n)=16+(6-1)32=176

Click here to see answer by josgarithmetic(39617)

Question 1011566: The sum of the first n terms of an arithmetic sequence is (2n^2)-n. Find the general term and show that the sequence is an arithmetic sequence
Click here to see answer by MathLover1(20850)

Question 1011598: what is the similarity between 85,17,19,4 and 2
Click here to see answer by Alan3354(69443)

Question 1011636: What is the similarity between numbers, 85 19 17 4 2:
Click here to see answer by Alan3354(69443)

Question 1011672: How many terms in the series 5+9+13=......+tn are less than 500? How many terms are neede for a sum of less than 500?
Click here to see answer by Boreal(15235)

Question 1011660: I need a well explained answer for the similarity between 85 19 17 4 2
Click here to see answer by Alan3354(69443)

Question 1011733: what is the similarity between 2,4,19,17 and 85

Click here to see answer by Fombitz(32388)

Question 1011821: The second term and fifth term of a Geometric Progression (GP) are 1 and 1�8 respectively. Find the common ration , first term and eight term.
Click here to see answer by josgarithmetic(39617)

Question 1011827: write 3 different series each with 5 terms and each with a sum of 100.
Click here to see answer by Edwin McCravy(20056)

Question 1011827: write 3 different series each with 5 terms and each with a sum of 100.
Click here to see answer by AnlytcPhil(1806)

Question 1011827: write 3 different series each with 5 terms and each with a sum of 100.
Click here to see answer by Theo(13342)

Question 1011935: What is the similarty between 85,17,19,4 and 2
Click here to see answer by Alan3354(69443)

Question 1012025: 5 9 17 33 ?
Click here to see answer by ValorousDawn(53)

Question 1012095: The fourth term of a geometric series is 10 and the seventh term is 80.
Find the common ratio, the first term and the sum of the first 20 terms( tl the nearest whole number)
James
Click here to see answer by josgarithmetic(39617)

Question 1011947: What are next two terms of sequence:
-1,2,12,40,.......
Click here to see answer by Edwin McCravy(20056)

Question 1012112: If the sum of n terms of a series is 2n^2+3n+4. Find the series and also its nth term.
Click here to see answer by ValorousDawn(53)

Question 1008641: sum of the numbers of the series:
6+9+21+69+261+........upto n terms

Click here to see answer by Edwin McCravy(20056)

Question 1012166: 1,5 14 30 what comes next

Click here to see answer by ikleyn(52787)

Question 1012262: what is the rule for sequence 2, -4, 8, -10, 14
Click here to see answer by macston(5194)

Question 1012259: So.. for my holiday homework i was told to find a formula to sum up the tetrahedral numbers.. which are 1, 4, 10, 20, 35, 56...
And im really stuck on where to start, could you please help me step by step to sum up consecutive tetrahedral numbers? (Would appreciate if its in a easy mathematical language)
Is there any tricks to find formulas or equstions from a sequence?
Thank you :"c
Click here to see answer by rothauserc(4718)

Question 1012113: if a,b,c in ap nd x,y,z in gp prove that x^b y^c z^a=x^c y^a z^b
Click here to see answer by fractalier(6550)

Question 1012510: A train averaged 120km/h for the first 80% of a trip and 90km/h for the whole trip. Find it's average speed for the last 20% of the trip.
Click here to see answer by ikleyn(52787)

Question 1012517: 3+5+6=72
5+5+6=94
5+6+7=85
5+5+3=73
9+4+7=?
Click here to see answer by ikleyn(52787)

Question 1012531: The sum of the eleven terms of AP is 286.If the eleventh term is 46.find the first term.
Click here to see answer by fractalier(6550)

Question 1012720: if first term of n A.P.'s is 1 and their respective common differences are 1,2,3,..........,n,then prove that sum of their n terms will be n(n^+1)/2
Click here to see answer by fractalier(6550)

Question 1012721: if first term of n A.P.'s is 1 and their respective common differences are 1,2,3,..........,n,then prove that sum of their n terms will be n(n^2+1)/2
Click here to see answer by fractalier(6550)

Question 1012745: When half the positive difference between the 13th and 23rd natural numbers is added to the 34th even natural number, what is the result? (The natural numbers are 1,2,3,4,...)
Click here to see answer by fractalier(6550)

Question 1012663: How could i make an equation for Von Koch curve?
I attempted it but no luck :/
I do not know where to start, so a help would be very nice :D
I need to make an equation for perimeter and the area, please write each steps if possible.
Im so dumb T.T
Click here to see answer by rothauserc(4718)

Question 1012909: Find the indicated terms of the following sequences
2,6,11,17,,,,,,,,,a7
Click here to see answer by fractalier(6550)

Question 1012149: Hey, i have a weird one for you, We are trying to figure out the next set of number/letters in this sequence. They are currently in order from 1-12.
ca1e2fce
fbe2b441
b11a634c
d2085828
ac658b15
bf0bba92
0b58b9fc
6912b084
0ecd3702
fdca62d7
88a2d829
fcbdfd41
Click here to see answer by fractalier(6550)

Question 1012940: find the value of n if the sum of n terms of the series 11 + 33 + 99 + ... is equal to 108 251.
Click here to see answer by ikleyn(52787)

Question 1012957: First 4 numbers in a geometric series sums to 30, sum to infinity is 32. Find the first 2 numbers in the series.
How do i even start on this :(
Click here to see answer by rothauserc(4718)

Question 1013420: what s the difference btn 85,17,19,4,2
Click here to see answer by Alan3354(69443)

Question 1013461: I can use the numbers 0, 1, 2, and 6.
I have to use each number and can only use each number once.
I can use any math formula or operation (add, subtract, functions, roots, powers, etc.)
How do I get the number 20? or 21?
Thanks.
Click here to see answer by fractalier(6550)

Question 1013501: If 8,x,y,z,32 give us an arithmetic progression(AP).Determine the sum of x,y,z.

Click here to see answer by fractalier(6550)

Question 1013540: I can use the numbers 0, 1, 2, and 6.
I have to use each number and can only use each number once.
I can use any math formula or operation (add, subtract, functions, roots, powers, etc.)
How do I get the number 10?
Thank you.

Click here to see answer by Alan3354(69443)

Question 1013654: A number sequence is as follows: 4, 8, 12, 16, 20, 24, .... If 4 is the 1st number in the sequence what is the sum of the first 300 numbers in the sequence?
Click here to see answer by fractalier(6550)

Question 1013624: What is the next missing number in 5,15,75,525
Click here to see answer by fractalier(6550)

Question 1013619: 5*5+7*7-9*9=100
Click here to see answer by Alan3354(69443)

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