some body please help im lost??

Question

anonymous · Answer

Larry has taken out a loan for college. He started paying off the loan with a first payment of $150. Each month he pays, he wants to pay back 1.3 times as the amount he paid the month before. Explain to Larry how to represent his first 15 payments in sigma notation. Then explain how to find the sum of his first 15 payments, using complete sentences. Explain why this series is convergent or divergent.

anonymous · Answer

i've completed every question except this one please someone help

geerky42 · Answer

You can represent sum like this: $$\Large \sum_{k=1}^{15}150\left( 1.3^{k-1}\right)$$
Or you can simplify it to $\Large \displaystyle 150\sum_{k=0}^{14}1.3^k$

anonymous · Answer

@geerky42 thnks can you explain in sentence im a little confused how you got that

geerky42 · Answer

umm, i'm not good with what word to use, but i try my best...

I got this sum because first payment is 150, so you have $1.3^0 = 1$ to multiply, then next month, you pay 1.3 times as the previous payment, so you have $1.3\cdot150$.
again, next month, you pay 1.3 times as pervious month payment $(1.3\cdot150)$ so you have $1.3\cdot(1.3\cdot150) = 1.3^2\cdot150$ and so on...

anonymous · Answer

@geerky42 thnks i kinda get it, and this just my review, hopefully my test isn't this difficult