How do you find the vertex of a parabola $y=-[x]^2+1$ ?

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Answer 1 · 2015-07-18T22:32:45

The vertex is at $color(red)((0,1)$ .

$y = -x^2+1$

The standard form of the equation for a parabola is

$y = ax^2+bx+c$ , so

$a = -1$ , $b = 0$ , $c = 1$

The $x$ -coordinate is at $x = -b/(2a) = -0/(2(-1)) = 0$

To find the $y$ -coordinate of the vertex, substitute $x =0$ into the equation to get

$y = -(0)^2 +1 = 0+1 = 1$

The vertex is at ( $0,1$ ).

graph{-x^2+1 [-3, 3, -5, 2]}

How do you find the vertex of a parabola y=-[x]^2+1y=-[x]^2+1?