February 12th 2018 archive

Week 2-Geometric sequences

This week we learned about geometric sequences and series. A Geometric sequence differs from an arithmetic sequence because instead of adding a common difference, a common ratio is multiplied by the term to get the next term.

the equation used to find a term in a sequence is

 

t_n=ar^{n-1}

in this equation t_1 is represented by a

for example: 5,10,20,40… find t_{10}

 

t_{10}=5(2)^{10-1}

 

t_{10}=5(2)^9

 

t_{10}=5(512)

 

t_{10}=2560

 

A finite geometric series can be found using the equation