1. anonymous

2. anonymous

do you want the whole steps or just a result? the final result is an = -7 *6^n

3. anonymous

a(n+1) -6 a(n) =0 characteristic equation is x -6 =0 x =6 the equation has the form an= C*6^n replace a1 = C *6^1 = -42 ---->C = -7 replace C into an form to get an= -7 *6^n Hope this help. are you in discrete math course?If so, you will understand what i mean

4. ParthKohli

LOL

5. anonymous

What's wrong? and what makes you laugh

6. anonymous

@ParthKohli : I am a student and want to study from others. Please tell me if I am wrong in my work, I appreciate when you correct my mistake or my flaw

7. ParthKohli

You have left a lot of space. :-)

8. anonymous

I don't know why the net post it up. I am not good at computer

9. ParthKohli

I think we can do this using the geometric sequence formula.

10. anonymous

yes, you are right. show me your work. now is your turn

11. ParthKohli

12. ParthKohli

$$a_1 = -42$$ and $$r = -6$$. Now use the following formula:$a_n = a_1 \times r^{n - 1}$

13. anonymous

how to get r?

14. ParthKohli

Strictly speaking, if you have:$a_{n + 1} = {\rm some ~number} \times a_n$For all $$n$$, then the "some number" is the common ratio denoted by $$r$$.

15. ParthKohli

I'd leave it to the asker to do the rest.

16. anonymous

I need help from my problem, may I have yours?

17. ParthKohli

18. anonymous

my problem is: find the coefficient of x^10 in the power series of (x^2 +x^4 +....) (x^3 +x^6 +x^9 +....)(x^4 +x^8 +x^12 +....)

19. ParthKohli

This is an interesting problem. Let's see.

20. ParthKohli

You can just message me here; I check this site much often... more than I check my email

21. anonymous

dealt. since I have to go. send me message when you've done. Nice to see.

22. ParthKohli

Cya!