Use QUADREG on your graphing calculator to find the polynomial.
y=3.5x^2-4.5x+5
Practice makes perfect
To find a quadratic model for the given values, we first have to enter them in our graphing calculator. Push STAT, choose Edit, then enter our values in the first two lists.
Finding the Equation
Next, push STAT and choose the second menu, CALC. By choosing the fifth option, the calculator will perform a quadratic regression.
Now we can substitute the values for a, b, and c into a quadratic equation, ax^2-bx+c.
y=3.5x^2-4.5x+5
Checking the Answer
Once the values have been entered, we can plot them by pushing 2nd and Y= and choosing one of the plots in the list. Make sure you turn the plot ON, choose scatterplot as the type, and use L1 and L2 as XList and YList. Finally, you can pick whatever mark you want.
By pushing GRAPH the calculator will plot the dataset. A standard viewing window might not show the data points, so we can change it if necessary.
Now, let's plot the function. Press Y= and enter our function.
As we can see, the model intersects all of the values. Because it has an r^2 of 1, we know the polynomial is a perfect fit.
