Find an explicit rule for the nth term of a geometric sequence where the second and fifth terms are -6 and 162, respectively.

Question

anonymous · Answer

U there

anonymous · Answer

BRO

miracrown · Answer

AFK

anonymous · Answer

Ok give me a sec just wanted to know if u were there

miracrown · Answer

----- , 6 , ------ , ------, 162

miracrown · Answer

So a geometric sequence is one determined by multiplying again and again by the same number. So we need to figure out what number to multiply -6 by two times and get 162 we could guess and check.

Pick a number to start ...

anonymous · Answer

Sorry the lags men

miracrown · Answer

Yea man, same here ;-;

anonymous · Answer

Take this as an example:
I can't let you cheat

anonymous · Answer

Also, 2304/(-36) is the 5th term divided by the 2nd term which is -64
That is also:   [(a)(r^4)] / [(a)(r)]  =  r^3   

So, r^3 = -64     and   r = -4

So, the 2nd term, -36, is (a)(r) = (a)(-4), so "a" = 9

We now have "a" and "r" and the general expression for the nth term is:

(9)(-4)^(n-1)

And remember that exponentiation takes precedence over multiplication, so only the 
"-4" is being raised to the "n-1" power.

anonymous · Answer

I know is a lot to throug at you.......