Posted by Erica on .
the design below grows each day, as shown. if the pattern continues to grow like this, how many tiles will there be in the design on the tenth day? on the fiftieth day?
Day 1 1 tile
Day 2 5 tiles
Day 3 13 tiles

Math 
Susan,
1+4(n1) where n is the day number
on day 10
1+4(101)=37
on day fifty
1+4(501)=197 
Math 
Steve,
Day 3 does not fit: 1+4*2 = 9
Since the difference is changing by 4 each day, we will have a quadratic:
Day n: 2n^2  2n + 1 
Math 
Sandro,
What do you mean by the ^ in your equation Steve? I don't really understand the 2n^22n+1. I did figure out it was a quadratic equation, and actually happened to figure out the entire problem until I noticed it said "Write a description or formula that allows me to figure out the number of tiles for any day number?"

Math 
Sandro,
Oh, ok, do you mean to cube the first number by the 2nd, get back to me... Thnx

Math 
Sandro,
Steve is wrong!!! D: