## anonymous 4 years ago Why does the addition sign change in 9^-(n+2) when you convert it to 1/9^(n-2)?

1. campbell_st

there is now change $9^{-(n +2)} = \frac{1}{9^{n + 2}}$ for a proof $\frac{1}{9^n} \times \frac{1}{9^2} = \frac{1}{9^{(n + 2)}} = 9^{-(n + 2)}$

2. anonymous

so what is happening in this step? http://tutorial.math.lamar.edu/Classes/CalcII/Series_Special_files/eq0020MP.gif

3. anonymous

oh. wait i think i get it. nvm