Answer:
Part 1: 19° C
Part 2: decay
Part 3: 11%
Don't drop out!! You'll hurt yourself if you do that! If you feel trapped/stuck, reach out for help from friends and teachers and parents. Find someone who can help you understand what you're learning and teach you. Study extra if you need to. But don't drop out.
Step-by-step explanation:
You've got the initial temperature down: the constant that the function multiplies is the initial condition/number/temperature/population/&tc. since that constant is 19, the initial temperature is 19° C.
However, this is not an exponential <em>growth</em> function. This is an exponential <em>decay</em> function. There are two ways to surmise this:
- The context of the problem is a soda can placed in a cooler. The temperature will <em>decrease</em>, right? This means the function is an <em>exponential decay function</em>.
- If the function given were an exponential <em>growth</em> function, then the number within parentheses (this is the percentage by which something changes) would be greater than 1. It isn't, and so the function is an exponential <em>decay</em> function
As for the percentage at which it is changing… erm, <em>decreasing</em>… that would be 100 times the difference of <em>1 – r</em>. Here, <em>r</em> is the number in parentheses. First, let's solve for 1 – <em>r</em>. Here, <em>r</em> is 0.89, so 1 – 0.89 = 0.11, and now we just need to multiply by 100. Why?
Percentages are a fraction of 100. For example, 89% is equal to 0.89 and the fraction . Here, we multiply 0.11 to find the percentage of change. So we have 0.11 × 100 = 11%, and our rate of change is 11%. Thanks to breyanamyers5 who indirectly hinted at my mistake here!
I hope this is the explanation you were hoping for! Have a great day, and <em>don't give up</em>!!
Wait a second... this question was <em>3 months old</em>. Whoops. Oh well.