/sci/ - Science & Math

[eqn] \big(9^{\frac{n+1}{2}}+9^{\frac{n}{2}}\big) = \big(9^{\frac{n}{2}}9^{\frac{1}{2}}+9^{\frac{n}{2}}\big) = 9^{\frac{n}{2}}\big(9^{\frac{1}{2}}+1\big) = 3^n\times4[/eqn]