PLEASE HELP ME! For a geometric sequence, if a1 = 2 and a5 = 1250, what is the value of r?
![PLEASE HELP ME For a geometric sequence if a1 2 and a5 1250 what is the value of r class=](https://us-static.z-dn.net/files/d2c/2ca218d452247c011cde9ba50cf64d2c.jpg)
Answer: r = 5
Steps:
[tex]a_n=ar^{n-1}[/tex]
1. add Values to formula
[tex]1250=2r^{5-1}[/tex]
2. get r alone
[tex]\frac{1250}{2}=\frac{2r^{4}}{2}[/tex] ➜ [tex]625= r^4[/tex]
3. get rid of the exponents
[tex]\sqrt[4]{625}= \sqrt[4]{r^4}[/tex] ➜ [tex]\sqrt[4]{625}= r=5[/tex]
r = 5