Part A - linear functions change at a constant rate.. while exponential functions change at a constant percent rate... that sounds the same but it's not. A linear function will go up (or down) the same amount when the time period is the same... like up 1,000 more visitors every month... if this happens, when you subtract the visitors for month 10-month 9, you will get the same answer as when you subtract he visitors for month 9-month 8.
An exponential function will go up by the same % when the time period is the same... so it'd be like if it went from 1,000 to 1,100 (that's up 100, which is 10% of 1,000) and then from 1,100 to 1,210 (that's up by 110, which is 10% of 1,100). If this happens you get the same answer when you divide the visitors for month 10 by the visitors from month 9 as you get when you divide the visitors for month 9 by the visitors from month 8. (sometimes because of decimals you only get really really close to the same but that counts).
This one is exponential because dividing gets you around 2.09 every time
Part B
Since dividing # of visitors by the # from the month before gets you around 2.09 each time, we multiply that by 100 to get the % version of the decimal.
So that's 209%... but that's not how much it changes by or grows by... that's what it ends up. It goes from itself (100%) to a bigger # (209%).. that's a 209-100 = 109% increase each month.
Part C
you need to think a little bit about what's going on in class.... becasue there are a bunch of different ways to do this. Sometimes you make an equation, sometimes you work backwards.
Here's one way... since multiplying visitors from week 8 by 2.09 gets you week 9 visitors.. and multipliying week 9 visitors by 2.09 gets you week 10... etc.... we can go backwards...
Week 7 visitors times 2.09 would equal the week 8 visitors
so, w(2.09)=5.74
if we divide both sides by 2.09 we get w is equal to about 2.7464... so the week 7 visitors is about 2.7464 (thousands) or 2,746.
Hope that helps
