Mathematics
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OpenStudy (anonymous):
What is the domain and range of the quadratic equation y = -3(x - 10)^2 + 5?
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OpenStudy (anonymous):
I don't know what range means
jimthompson5910 (jim_thompson5910):
what is the vertex of this parabola
OpenStudy (anonymous):
-3?
jimthompson5910 (jim_thompson5910):
in general
y = a(x-h)^2 + k
has the vertex (h,k)
OpenStudy (anonymous):
so its (-10,5)?
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jimthompson5910 (jim_thompson5910):
closer
jimthompson5910 (jim_thompson5910):
it's actually (10, 5)
jimthompson5910 (jim_thompson5910):
since h = 10 and k = 5
jimthompson5910 (jim_thompson5910):
the y coordinate of this vertex is y = 5
this is either the min or max that y can be
do you know which it is (min or max)?
OpenStudy (anonymous):
I have no idea
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OpenStudy (anonymous):
ill say min
jimthompson5910 (jim_thompson5910):
the leading coefficient is a = -3
jimthompson5910 (jim_thompson5910):
so this means that the parabola opens downward
so this means there is a maximum, which is the vertex
jimthompson5910 (jim_thompson5910):
so y = 5 is the largest possible y value on the graph
jimthompson5910 (jim_thompson5910):
how does that help us find the range?
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OpenStudy (anonymous):
because y=5 is the largest possible y value on the graph
jimthompson5910 (jim_thompson5910):
yes how can you use that to find the range
jimthompson5910 (jim_thompson5910):
and what is the range
OpenStudy (anonymous):
idk :'(
jimthompson5910 (jim_thompson5910):
the range is the set of all possible output values of a function, ie the set of all possible y values
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jimthompson5910 (jim_thompson5910):
so if you know the max y value you can use this to find the range
OpenStudy (anonymous):
so the range is 5?
jimthompson5910 (jim_thompson5910):
not just 5, but it includes other values as well
OpenStudy (anonymous):
greater than?
jimthompson5910 (jim_thompson5910):
what's another value that's in the range?
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OpenStudy (anonymous):
1)Domain: All Real Numbers
Range: y alt= 5
2)
Domain: All Real Numbers
Range: y alt= 5
OpenStudy (anonymous):
I have two answers to choose, which one would it be?
OpenStudy (anonymous):
number 1 is less than 5, and number 2 is greater than 5
jimthompson5910 (jim_thompson5910):
what's another y value that is in the range
OpenStudy (anonymous):
10
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jimthompson5910 (jim_thompson5910):
remember y = 5 is the largest possible y value (the parabola opens downward, so it peaks)
OpenStudy (anonymous):
I say greater than 5
jimthompson5910 (jim_thompson5910):
here's what the parabola looks like
|dw:1376181401228:dw|
jimthompson5910 (jim_thompson5910):
the peak is here (so the vertex is here)
|dw:1376181415643:dw|