katiebugg 3 years ago help?!?!?!?! find the variables not given a1 = 10, r = 3, n = 5

1. jim_thompson5910

This looks like a geometric sequence

2. katiebugg

it is

3. jim_thompson5910

an = a1*r^(n-1) is the general formula

4. jim_thompson5910

In this case, a1 = 10 and r = 3, so an = 10*3^(n-1)

5. jim_thompson5910

the nth term, an, in this case is the 5th term since n = 5 so a5 = 10*3^(5-1)

6. jim_thompson5910

or an = 10*3^(5-1) when n = 5

7. subjectgeek

High school math or what?

8. sauravshakya

so,|dw:1343971838905:dw|

9. jim_thompson5910

does that make sense?

10. katiebugg

.... no

11. jim_thompson5910

I'm assuming you want to find an right?

12. jim_thompson5910

The term \(\Large a_{n}\)

13. katiebugg

yess its the one missing

14. jim_thompson5910

\[\Large a_{n} = a_{1}r^{n-1}\] \[\Large a_{n} = 10*3^{n-1}\] \[\Large a_{n} = 10*3^{5-1}\] I'll let you finish

15. katiebugg

lol thanks

16. jim_thompson5910

you're welcome, tell me what you get

17. katiebugg

810???

18. jim_thompson5910

you are correct

19. katiebugg

lol yay!!!!!! soo i just do that when looking for then An then lol

20. jim_thompson5910

exactly

21. jim_thompson5910

\(\Large a_{n}\) is the nth term. So in this case, when n = 5, \(\Large a_{n}\) is the 5th term Another way to say this \(\Large a_{5}\)

22. katiebugg

lol ok