help me plz......................

Question

Use the minimum or maximum feature of a graphing calculator to approximate the vertex of the graph of y=-6.2x^2+4.8x-1y

Use the minimum or maximum feature of a graphing calculator to approximate the vertex of the graph of =−πx²+3x​ . 

Answer 1

The graph opens downward because the "a" term is negative, so the vertex will be a maximum.

Its x coordinate is -b/2a = -4.8/(2)(-6.2) = -4.8/-12.4 = 0.387. See if your graphing calc gives same result.

Can do the same test with the 2nd equation.

Answer 2

Hello Ethan. I'm not sure what you are using for a graphing calculator, so I will explain how it works with a TI-89 since that is the type I always use. You first need to type in the equation(s) you are graphing. For the 89, you hit the green diamond function key and then the F1 key. This will open up what is called the "Y-editor" where you can type in your equation, and make sure to hit "Enter" to make sure the equation goes in as the Y-1 equation ( or whatever number of equation you are typing in). Then you need to set the grid size for the graph, so to do this you hit the green diamond function key followed by the F2 key which takes you into what is called the "window settings". This is where you set the range of values for both the x-axis and the y-axis and the increment by which you want to space the x and y axes ( known as the x-scale and the y-scale). At this point, you are ready to graph, so you hit the green diamond function key again, followed by the F3 key, and this will graph your equation on the grid that you have set up.

Once it is graphed, you then hit the F5 key while in your graph and scroll down to the max or min function. For either one, you will need to set the lower and upper boundaries for where you want the calculator to look to identify the max or min. When you hit the F5 key, it will automatically ask you for the "lower bound". At this point, just make sure your cursor is somewhere to the left of the max or min; if it is not, use your left arrow to position it so. Then hit "Enter" and do a similar thing when it asks you for the "upper bound". Once you have the boundaries set, your calculator will do the rest, finding either the max or the min and indicating what it is right there on your screen, down at the bottom, giving you the x- and y- coordinates.

I hope this helps! Other graphing calculators may vary somewhat in how they do this, but the basic steps should be the same. Good luck!