Hello,
[tex] u_{1} =a\\
u_{3} =b\\
q= (\dfrac { u_{3} } {u_{1 } } )^ \frac{1}{2} \\\\\\
=(\dfrac{b}{a}) ^ \frac{1}{2} \\
u_{n+1} =a*q^{n}=a* (\dfrac{b}{a}) ^ \dfrac{n}{2} \\
\\\\\\\\\\\\v_{1} =a\\
v_{5} =b\\
r= (\dfrac { v_{5} } {v_{1 } } )^ \frac{1}{4} \\\\\\
v_{2n+1} =a*r^{2n}\\\\
=a* (\dfrac{b}{a}) ^ \dfrac{2n}{4}\\\\
=a* (\dfrac{b}{a}) ^ \dfrac{n}{2} \\
[/tex]