1. ## expressions

hi, i have a math problem

Term ......... . . Pattern
_________l__________________

...1 ............. 2
... 2 ............. 6
...3 ............. 18
...4 ............. 54
...5 ............. 162

so the pattern is start at 2 times 3 each time. but i need a expression

ex. n+5

N is the term, N and something else has to give me the pattern

2. Originally Posted by ashimashi
hi, i have a math problem

Term ......... . . Pattern
_________l__________________

...1 ............. 2
... 2 ............. 6
...3 ............. 18
...4 ............. 54
...5 ............. 162

so the pattern is start at 2 times 3 each time. but i need a expression

ex. n+5

N is the term, N and something else has to give me the pattern

This is a geometric sequence, with $\displaystyle t_1 = 2, r = 3$.

In a geometric sequence $\displaystyle t_{n + 1} = rt_{n}$.

So $\displaystyle t_2 = 3\cdot 2$

$\displaystyle t_3 = 3\cdot 3 \cdot 2$

$\displaystyle t_4 = 3\cdot 3\cdot 3 \cdot 2$...

Can you see that $\displaystyle t_{n + 1} = 2\cdot 3^n$?

3. kk thank you