Take Home Quiz!

This weekend, please complete the quiz that we started (in groups) in class! Don't forget!

Here's a hint for the last question:

• This question tells us that the element decays continuously. This tells us which formula to start with!
• The only reason this tells us that it's a daily rate is so we know that we can substitute numbers of days in for t, rather than years. (It has nothing to do with "n").
• Consider the rate....because this element is decaying, we have to use a negative rate (-r) in our equation!
• Part (c) asks us for the half-life. This means we have to try to estimate the value of t (the number of days) that it will take for our initial amount to decay to half (of the original amount). In other words, since our element started at 50 grams, we need to estimate the value of t when the amount will be at 25 grams.
• There are three ways to do this:
• 1.) "guess and check." Substitute different numbers for t! Try decimals too!
• 2.) Use the table feature of your calculator (after putting your equation in Y1) to see when the amount (Y) is at 25!
• 3.) Use the graph of the function. Look at the graph and trace along the curve to find out the x-value when y = 25!

If you lost your paper or were absent, you can find the quiz below. Enjoy!