Find the domain and range of the function y= -3(x-1/3)^2+4/3

5 answers

as with all polynomials, the domain is (-∞,∞)
Since the graph is a parabola, it has vertex.
The leading coefficient is negative, so the parabola opens downward.
So, the range is everything which is below the vertex: (-∞, 4/3]
Your equation is in the usual vertex form.
You can read off the vertex to be (1/3 , 4/3)
You also know that the parabola opens downwards (from the -3),
so your vertex is a maximum.
Of course the domain of such a parabola is the set of real numbers.
Tell me what you think about the range.
@oobleck I don't understand
@Reiny the range would be 4/3?
The range would be :
y ≤ 4/3 , y ∊ R
or as oobleck stated, (-∞, 4/3]