McGraw Hill Glencoe Algebra 1, 2012
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McGraw Hill Glencoe Algebra 1, 2012 View details
5. Exponential Functions
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Exercise 20 Page 427

a The function models the growth of bacteria population.
Here, is the number of hours. Since corresponds to the elapsed time is hours until Hence, we need to substitute for in the function.
Evaluate right-hand side
The number of bacteria is about at
b Let's see how the graph looks like in the graphing calculator.
We see that the intercept is It represents the number of bacteria in the culture at or Since represents time, a reasonable domain is all non-negative real numbers. At the number of bacteria is so a reasonable range is all real numbers greater than or equal to

Showing Our Work

Drawing the function
To draw we need to change the variables.
Push the button and enter the equation in the first row.
Solution4701 abcd.svg

Push and the calculator will draw the equations. For this function to be visible on the screen, re-size the standard window by pushing the button. Change the settings to a more appropriate size and then push

Solution4701 321sd2s44.svg
Window with a graph

To find the intercept, we can use the trace feature to find the value of the function at This can be done by pressing and choosing the value option. Finally, enter and it will give you the intercept.

Since and represent the same thing, the intercept is