Today I was in my math class (FST) and we were working on Arithmetic and Geometric series. Some easy stuff you know. And the first problem had to do with investments and interest. It went something like:
You invest $500 at 12.5% interest on the first year. Then on the next year you invest more but also an additional $50. Interest is still 12.5%. How much money will you have after 40 years? (Annual Interest).
So it looks like this:
Year 1 - 500$ + Interest
Year 2 - 550$ + Interest + (Money from previous year after interest + Interest)
Year 3 - $600 + Interest + (Money from previous year after interest + Interest) + (Money from 2 years ago after 2 interests + interest)
So you get the point.
She got the answer using a formula that looks like this:
Summation: Expression + Summation: Expression
but I wanted something shorter and I mad a formula like this:
She looked at it and she said "Yeah, That seems like it would work". I plug in my numbers, she looks at the answer and says, "Nope. That's wrong. But I'll take a look at it."
I go to clubs and then 3rd hour, followed by 4th hour. I work on a proof during 3rd hour for about 15min proving that mine should be right. Next thing you know, I come talk to her after 4th hour and she's like "Yeah, you were right I was wrong. I went to talk to Mr.******* (Best math teacher at school) and he agreed with you, also was very impressed."