Finding the Vertex

[SWood]

I need to find the vertex of
y=(-1/2)x^2 + 2x + 10

I tried
x=-2/2(-1/2)
x=-2/-1
x=2

So...

y= f(-2) = (-1/2)(2)^2 +2(2)+10 = 16

Vertex is (2,16)

But I was told that was wrong...

 

[Aladdin]

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Find the derivative & set it equal to zero. . .

 

[SWood]

Derivitive?

 

[Aladdin]

Derivitive?

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Allright . . .


The vertex of a parabola is ax^2 +bx+c is located at x=-b/(2a)

Your parabola has a=-1/2 , b=2

So the vertex is located at x=2

Replace y(2) you get 12

So the coordinates of your vertex is at (2,12).

Many Smiles,
Aladdin :wink:

 

[SWood]

Thank you!