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 942889: Two consecutive odd numbers have a sum of 44. Find the value of the product of both of these odd numbers?
Click here to see answer by macston(5194)

Question 942975: i got 7 1/3 for the first term and 1/3 in the seventh term what is the sequence

Click here to see answer by richard1234(7193)

Question 943075: I cannot understand how (7-1)^2 equals 36 but 7�7-1-1 equals 47 what am I doing wrong?
Click here to see answer by richard1234(7193)

Question 943075: I cannot understand how (7-1)^2 equals 36 but 7�7-1-1 equals 47 what am I doing wrong?
Click here to see answer by MathTherapy(10552)

Question 943110: proove that the n th term of an AP can not be n square 1. justify your answer
Click here to see answer by richard1234(7193)

Question 943111: proove that the n th term of an AP can not be n^2 + 1. justify your answer
Click here to see answer by richard1234(7193)

Question 943188: (38 ⋅ 2−5 ⋅ 90)−2 ⋅ 2 to the power of negative 2 over 3 to the power of 3, whole to the power of 4 ⋅ 328 (5 points)
Write your answer in simplified form.
Click here to see answer by stanbon(75887)

Question 942410: first negative terrm of the sequence 20,77/4,37/2,71/4
Click here to see answer by Edwin McCravy(20056)

Question 943563: Evaluate the function for x = �4c if c = �2.
f(x)=-3xx2-4x
Click here to see answer by Fombitz(32388)

Question 943611: two numbers are in the ratio 4:5. If their sum is 54, find the numbers
Click here to see answer by TimothyLamb(4379)

Question 943600: The third and the eight terms of a geometric progression is 21. The third term exceeds the second term by 6. Find the common ratio.
Click here to see answer by stanbon(75887)

Question 943637: are these numbers arithmetic or geometric and why? 52, 47, 42, 37
Click here to see answer by reviewermath(1029)

Question 943639: What is the next three series of numbers in 6400, 3200, 1600, 800 and why? Are they arithmetic or geometric?

Click here to see answer by rfer(16322)

Question 943639: What is the next three series of numbers in 6400, 3200, 1600, 800 and why? Are they arithmetic or geometric?

Click here to see answer by MathTherapy(10552)

Question 943739: What is the next number in this pattern? 6, 18, 35, 62, 109, ____ . I have try adding going up.I multied.
Click here to see answer by richard1234(7193)

Question 943917: How many terms are in the sequence: 640,320,160,.......,5?
Click here to see answer by macston(5194)

Question 943917: How many terms are in the sequence: 640,320,160,.......,5?
Click here to see answer by dkppathak(439)

Question 944241: Which set of line segments could create a right triangle?
15, 30, 35
15, 36, 39
15, 20, 29
5, 15, 30
Click here to see answer by Edwin McCravy(20056)

Question 944241: Which set of line segments could create a right triangle?
15, 30, 35
15, 36, 39
15, 20, 29
5, 15, 30
Click here to see answer by MathTherapy(10552)

Question 944285: Hello,
How can I find and d if
and ?
I am not sure which formula to use.
Thanks so much.
Click here to see answer by stanbon(75887)

Question 944285: Hello,
How can I find and d if
and ?
I am not sure which formula to use.
Thanks so much.
Click here to see answer by MathTherapy(10552)

Question 944299: i need help please can anyone tell me what is the next number in the series of following numbers 701495 , 841853 , 676836
please its urgent
Click here to see answer by Edwin McCravy(20056)

Question 944648: please help solve these two problems:
sequence 4,8,16,32,64,128�
d=2
a sub 1=4
prob #1: a(3) what is a? is that the same as a sub exponent 1 which is 4?
prob #2: a(1)+a(7)
Thank you
Click here to see answer by stanbon(75887)

Question 944201: if a,b,c are in H.P then (1/a + 1/b - 1/c)(1/b + 1/c - 1/a)=?
Click here to see answer by Edwin McCravy(20056)

Question 945027: 75, 85, 95, 105 geometric or arithmetic
Click here to see answer by amarjeeth123(569)

Question 945097: Determine the number of terms n in each arithmetic series.
Problem 1: a1= 4, d = 7, Sn= 228

Problem 2: (−2) + (−12) + (−22) + (−32)..., Sn= −224
These problems stumped me...thanks in advance for your time and effort, I appreciate the help!
Click here to see answer by nerdybill(7384)

Question 941989: Use mathematical induction to prove that:
n
∑ r^2/{(2r-1)(2r+1)}= n(n+1)/(2(2n+1))
r=1
Thanks!!
Click here to see answer by Edwin McCravy(20056)

Question 945337: Find the nth term of 5,8,11,15
Click here to see answer by amarjeeth123(569)

Question 945364: sum the serie: 1+5+9+...+77
Click here to see answer by josgarithmetic(39618)

Question 945179: IF 3(5/9) AND 40(1/2) ARE THE FIRST AND THE LAST TERMS RESPECTIVELY, OF A GEOMETRIC SEQUENCE, DETERMINE THE VALUE(S) OF THE FIFTH TERM IF THERE ARE SEVEN TERMS IN A SEQUENCE
Click here to see answer by KMST(5328)

Question 945195: construct an expression tree for the following expression:
((1+5)/1-4)*(16+(4*(5-8)))

Click here to see answer by Edwin McCravy(20056)

Question 944497: Find the 8th term of the sequence below.
a1 = 4 r = 7

Click here to see answer by Fombitz(32388)

Question 944497: Find the 8th term of the sequence below.
a1 = 4 r = 7

Click here to see answer by MathTherapy(10552)

Question 941377: the sum of n terms of 1�/1 + (1�+2�)/2 + (1�+2�+3�)/3+.......is
a)(n/36)(4n�+15n+17) b) (n/36)(4n�-15n-17) c)(n/36)(4n�-15n+17) d) none
Click here to see answer by Edwin McCravy(20056)

Question 945574: Generate the first five terms in of an arithmetic sequence, and write directions on how to find the 10th, 11th, and 12th terms of the sequence using a calculator in two different ways.

I have no idea how to approach this. any help would be greatly appreciated!
Click here to see answer by richard1234(7193)

Question 945504: What is the summation notation ofthe sum of the positive even integers less than 10
Click here to see answer by richard1234(7193)

Question 945683: why is the problem shown not factorable with rational numbers:
1-xy-20x^2 y2
Click here to see answer by Alan3354(69443)

Question 945965: identify the pattern... 1,5,2,10,3,15,4,_
Click here to see answer by jim_thompson5910(35256)

Question 946119: find the minimum number of AP 1,8,15............. such that the sum is greater than 1000
Click here to see answer by Fombitz(32388)

Question 946429: if a-b=3 an a2-b2= 36, then find the sum of both the variables of a and b.
Click here to see answer by jim_thompson5910(35256)

Question 946499: Find the nth term of the sequence:
1,-3,9,-27,81
Click here to see answer by Fombitz(32388)

Question 946510: SUM OF 8TH TERM OF A.P IS 160 WHILE THE SUM OF 20TH TERM IS 800.FIND THE 43TERM AND THE SUM OF THE 12TERM.

Click here to see answer by Fombitz(32388)

Question 946599: What is the sum of all positive integers less than 20 that cannot be written as the sum of 2 prime numbers?
Click here to see answer by richard1234(7193)

Question 946686: 8th term and expicit formula.
1,5,25,125
Click here to see answer by stanbon(75887)

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