Resolver varphi4a(4/5)^3*(4/5)^-6=(4/5)^2N-1

$$\varphi 4 a ( \frac { 4 } { 5 } ) ^ { 3 } \times ( \frac { 4 } { 5 } ) ^ { - 6 } = ( \frac { 4 } { 5 } ) ^ { 2 N - 1 }$$

Resolver N

$$N=-\frac{-\ln(a\phi _{4})+\ln(\frac{16}{25})}{2\ln(\frac{4}{5})}$$

$$\left(\phi _{4}<0\text{ and }a<0\right)\text{ or }\left(\phi _{4}>0\text{ and }a>0\right)$$

Resolver a

$$a=\frac{\left(\frac{16}{25}\right)^{N+1}}{\phi _{4}}$$

$$\phi _{4}\neq 0$$