Question 970773: Write a quadratic function in starndard form whose graph passes through the given points. (USE Stat)
(-4, -7), (-3,3), (3, -21)
Find the maximum heights.
What is the approximate difference in the maximum height for the parabolas?
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! With these three points and quadratic regression,
a=-2
b=-4
c=9
-2x^2-4x+9 = y(x)
(-1,10.8) is approximate
vertex is at x=-1,11 by the formula
Calculator:
Go to STAT and choose 1 Edit. Put the x values in L1, hitting enter after each one, then put the y values in L2, doing the same. Then second MODE, to get out.
Got to STAT CALC and hit 5, for quadratic regression. Then do 2nd 1 COMMA 2nd 2, COMMA then VARS Y-VARS and hit 1. That will give you the a, b, and c.
To graph, go to 2nd Y= for STAT PLOT and for Plot 1 hit enter
Scroll down to scatter plot and hit enter
Then scroll down to x-list and hit L1
For y-list hit L2
For Mark hit enter
Then graph, using the appropriate window.
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