Big Ideas Math Algebra 1, 2015
BI
Big Ideas Math Algebra 1, 2015 View details
1. Graphing Square Root Functions
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Exercise 51 Page 550

Practice makes perfect
a Consider the given function for the radius r of a circle given its area A.
r=sqrt(A/π) In order to find its domain we will first notice that since this is a square root function, the radicand cannot be negative. A/π≥0 ⇒ A≥ 0

Furthermore, the circle must have an area other than 0, otherwise it would be just a point. A>0 Let's graph this function in our graphing calculator! We will use x as the independent variable and y as the dependent variable, as these are the only variables we are allowed to use in the calculator. A ⇔ x r ⇔ y Now, press Y= and type the function.

Before we push GRAPH, we will change the window settings in order to take a better look at the graph. This can be done by pressing WINDOW and changing the window settings.

Now, we push GRAPH.

b In order to find the area of a circle with a radius of 5.4 inches we will use the trace feature of our graphing calculator. We push TRACE and move the cursor until y is about 5.4.

We found that the area of a circle with a radius of 5.4 inches is about 91.91 inches squared. Please note that this is not the only answer, as the cursor position may differ from calculator to calculator.