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 867268: 3, -6, 12, 4, 20, ?
Click here to see answer by MathTherapy(10552)

Question 871743: Find the common ratio and the next term for the sequence shown if possible. And perhaps how you got to that? Thanks!
Squence: 333 1/3, 250, 187 1/2.
Click here to see answer by richwmiller(17219)

Question 873094: find the seventh term in the geometric sequence 3/64,-3/16,3/4,-3
I have gotten through the first few steps but then when i put in my calculator i get a smaller number and the number should be larger.
An=a1r^n-1
A7=(3/64)x(-1/4)^7-1
but then i get =o.oooo114440918
Click here to see answer by stanbon(75887)

Question 873214: The first term of a sequence is 4. The fourth term is 1/2. Determine the second and the third term
Click here to see answer by oscargut(2103)

Question 873153: write a formula for the general term (the nth term) of the geometric sequence.
1 1 1 1
- - - -
2, -10, 50, - 250, ...
Click here to see answer by Fombitz(32388)

Question 873298: use S(n)=a1 (1−rn ) / (1−r) to evaluate the series 1/3+1/9+1/27+1/81
Click here to see answer by ewatrrr(24785)

Question 873318: how do you solve this problem using recuesive rules? 45,15,5,5/3,5/9
Click here to see answer by Fombitz(32388)

Question 873318: how do you solve this problem using recuesive rules? 45,15,5,5/3,5/9
Click here to see answer by ewatrrr(24785)

Question 873316: will you show me ho to solve this problem using recursive rules? 2/5,1/15,1/90,1/540,1/3240
Click here to see answer by ewatrrr(24785)

Question 873395: Consider the geometric seq.
2, 2√2, 4, 4√2, .....
1.) What is the common ratio, r?
2.) Find the 10th tern in the seq.

Click here to see answer by ewatrrr(24785)

Question 873527: What is the 9th term of the following geometric sequence? Enter a whole number.
7/9,-7/3, 7, -21, 63, ...
Click here to see answer by richwmiller(17219)

Question 873525: evaluate each series to the given term
-5 -25 -45 -....; 9th term
Click here to see answer by richwmiller(17219)

Question 873553: Find the sum of the infinite geometric series
-12 + 48/5 - 192/25 + ...
here are the answer choices
A) negative 40/3
B)negative 80/3
C) negative 20/3
D) negative 10/3
thank you!
Click here to see answer by richwmiller(17219)

Question 873559: Which would you rather have: A job that pays $1000 for 30 days or a job that pays you a penny on the first day, 2 pennies on the second day, 4 pennies on the third, 8 pennies on the forth and continues each day for 30 days? Show mathematical evidence to support your answer.
Click here to see answer by htmentor(1343)

Question 873647: Let a sequence {an} : 2, 5, 8, 11, ......, an. If an>100, the minimum value of n is __?__
Click here to see answer by ewatrrr(24785)

Question 873740: What's the next number in this sequence:
1000, 300, 90, 27, ___
Click here to see answer by Fombitz(32388)

Question 874005: What is the third term in the pattern with formula 8 � 4n � 1?

A. 64

B. 96

C. 128

D. 512
Click here to see answer by Fombitz(32388)

Question 873556: Arithmetic series: 1,3,6,10,15... What is the 8th term?
Click here to see answer by richwmiller(17219)

Question 874094: How do I figure out what number is the smalles
.999 .8 8 5 .3

&when there like this
1/2 1/4 5 2 3/4
Click here to see answer by Fombitz(32388)

Question 874159: Is there an easy way to memorize the formulas for geometric and arithmetic series & sequences and to figure out a specific term?
Click here to see answer by richwmiller(17219)

Question 873472: What is the sum of 75 terms when the sequence is 5, 12, 29, 41
Click here to see answer by richwmiller(17219)

Question 874586: what is the pattern in this sequence: 1, 10, 25, 55, 109, 196, and 325
Click here to see answer by KMST(5328)

Question 874686: A gardener brought 5 rabbits, after 2 months rabbits became 10, and after 4 months they became 20. If the growth continues on the same ratio, what would be the amount of rabbits after 1 year?
Click here to see answer by dkppathak(439)

Question 874777: Henry drove his car 208 miles. The car used 7.05 gallons of gasoline on the drive. Estimate the car's gasoline mileage in miles per gallon.?
Click here to see answer by ewatrrr(24785)

Question 875066: 32, , 24, 20, 16, , 8
What are the missing numbers?
Click here to see answer by ewatrrr(24785)

Question 875095: 54, 61, , 75, 82
What is the missing number?
Click here to see answer by josgarithmetic(39618)

Question 875615: If the nth term is 3n-1 then why isn't 85 a term in the sequence
Click here to see answer by richard1234(7193)

Question 875594: I am having trouble figuring out this question:
total sum 30= 15, 13, 11, 9, 7, 5, 3, 1
add 5 total numbers from the sequence above to equal 30, you can use the same number more than once.
Click here to see answer by richard1234(7193)

Question 875691: The measures of two complementary angles are in the ratio 4:1. What is the measure of the smaller angle?
a.
15�
c.
24�
b.
18�
d.
36�

Please select the best answer from the choices provided

A
B
C
D
Click here to see answer by ewatrrr(24785)

Question 875374: Find the standard deviation of the set of numbers in the arithmetic progression 4,10,16,22,........,154
Click here to see answer by richwmiller(17219)

Question 875964: The first two terms of the sequence are 2 and 5 what are the next TWO terms ?
Click here to see answer by josgarithmetic(39618)

Question 875975: the question really is : The rule for the next term of a sequence is : multiply the previous term by 3 and subtract 1
then its says the first two terms of the sequence are 2 and 5 and write down the next two terms
I just don't get it
Click here to see answer by ewatrrr(24785)

Question 876128: solve this pattern
625, 125, 25, _, _
Click here to see answer by josgarithmetic(39618)

Question 875786: A gardener is making a triangular planting, with 46 plants in the front row, 41 in the second row, 36 in the third row, and so on. If the pattern is consistent, how many plants are there altogether?
Click here to see answer by richwmiller(17219)

Question 876874: The first term in the sequence is 400. Every subsequent term is 20 less than half of the immediately preceding term . What is the fourth term in the sequence?
Click here to see answer by richwmiller(17219)

Question 876955: Can someone please help me?
1. Find the sum of each arithmetic series.
Part I: -15 + -3 + 9 + 21 + 33 + 45 + 57 + 69 + 81 + 93
Step 1: The formula for the sum of an arithmetic series is , where Sn is the sum of the terms in the series, n represents the number of terms in the series, a1 is the first term in the series, and an is the nth term in the series.
Find the value of each of the following:
a1 =________, an = ________, and n = ________. (1.5 points; 0.5 points each)
Step 2: Use the formula to find the sum. Show your work.

Click here to see answer by josgarithmetic(39618)

Question 877028: Find the sum of the series 10 + 20 + 30 + 40.

Click here to see answer by richard1234(7193)

Question 877111: I need help with this problem ASAP, I don't understand any of it at all. [Use the recursive rule to find the third term in the sequence. a_1=6 and a_n = a_n-1 + 3 ]
Click here to see answer by rothauserc(4718)

Question 877110: Please help me, I don't understand I've tried it and came up with -1874571.4 but I know the answer is 714.5. Could you please show me the steps...
*** Find the partial sum of the geometric series. S9 for 1000-400+160-64+...
Click here to see answer by rothauserc(4718)

Question 877150: The recursive formula for the arithmetic sequence 11,18,25,32,39.....
Click here to see answer by jim_thompson5910(35256)

Question 877326: Find the sixth term of the sequence
2, 6, 12, 20, 30,...
Click here to see answer by AnlytcPhil(1806)

Question 877326: Find the sixth term of the sequence
2, 6, 12, 20, 30,...
Click here to see answer by josgarithmetic(39618)

Question 877390: In the following series
1, 3, 7, A, 31, B
What is the value of A and B?
Click here to see answer by richard1234(7193)

Question 877472: What is the tenth term of the sequence that has a common ratio of 1/3 and 36 as it's fifth term?
Click here to see answer by fcabanski(1391)

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