Thread: Geometric sequences and series

1. Geometric sequences and series

I need help with these question can some 1 please gice me the answer to them so i can find how to find the answer by itself thanks

1. State the Common Ratio of the following Geometric sequence
3/4 , 3/10 , 3/25 , 6/125

2. In the Arithmetic Sequence below, X = ___
100 , ___ , _X_ , 64

3. For the Geometric Sequence below, X = ___
_X_ , 48 , ___ , ___ , 6

4. Given the sequence 15 , 9 , 3 , -3 ... t 20 = ___

5. Given the sequence 27/8 , 9/4 , 3/2 , 1 ... t 14 = ___ (write as a fraction)

6. State the next 3 terms and state the pattern in WORDS:
a) 4, 9, 15, 22, ....
b) 1, -3, 9, -27, ..

7. Write the first five terms of the sequence defined by the recursive formula:

t1 = 2 , tn = 1 / tn-1

8. For the geometric series 6 + 3 + 3/2 + 3/4 + .... find: (leave you answer as a fraction in lowest terms)
a) the tenth term
b) the sum of the first ten terms

9. In a geometric sequence t5 = 48 and t8 = 384. Find tn.

10. Evaluate: 20 + 14 + 8 + ..... + (-70)

11. In an arithmetic series t1 = 6 and S9 = 108. Find the common difference and sum of the first 20 terms

12. In an arithmetic series, S11 = 297 and S24 =1428, find tn

13. A doctor prescribes 200 mg of medication on the first day of treatment. The dosage is halved each day for one week. To the nearest milligram what is the total amount of medication taken by the patient after 1 week?

2. Show your work , ...............thats too! many questions at a time

3. Originally Posted by temour321
please gice me the answer to them so i can find how to find the answer by itself
Actually, that's not how it works. If you don't understand the "how" or "why", a list of numbers (being the solutions) will provide you with no useful information.

To learn the basics of sequences and series, try here. Once you have learned the necessary background material, please attempt the exercises. If you get stuck, you will then be able to reply with a clear listing of your work and reasoning so far, such as, for example, what you got when you did the divisions for the first exercise.

4. Note: You were given some of the solutions a week or so ago. It would nice if you showed some effort at some point...?