Find the best answers to your questions at Westonci.ca, where experts and enthusiasts provide accurate, reliable information. Get immediate answers to your questions from a wide network of experienced professionals on our Q&A platform. Get detailed and accurate answers to your questions from a dedicated community of experts on our Q&A platform.

Determine if the sequence is geometric. If it is, find the explicit formula and recursive formula.
3,18,108,648

Sagot :

[tex]a_1=3;\ a_2=18;\ a_3=108;\ a_4=648\\\\if\ a_n\ is\ a\ geometric\ sequance\ then\ \frac{a_2}{a_1}=\frac{a_3}{a_2}=\frac{a_4}{a_3}\\\\check:\\\\\frac{a_2}{a_1}=\frac{18}{3}=6\\\\\frac{a_3}{a_2}=\frac{108}{18}=6\\\\\frac{a_4}{a_3}=\frac{648}{108}=6\\\\correct!\\\\It's\ a\ geometric\ sequence[/tex]

[tex]The\ formula\ of\ geometric\ sequence:a_n=a_1r^{n-1}\\\\a_1=3;\ r=\frac{a_2}{a_1}=6\\\\therefore\\\\a_1=3\cdot6^{n-1}=3\cdot6^n\cdot6^{-1}=3\cdot6^n\cdot\frac{1}{6}=3\cdot\frac{1}{6}\cdot6^n=\boxed{\frac{1}{2}\cdot6^n}[/tex]
Thank you for visiting our platform. We hope you found the answers you were looking for. Come back anytime you need more information. We hope you found what you were looking for. Feel free to revisit us for more answers and updated information. Thank you for trusting Westonci.ca. Don't forget to revisit us for more accurate and insightful answers.