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How do you find the vertex of a quadratic function? Find the vertex of quadratic function y = x2 + 2x - 2 .
We will use the concept of differentiation in order to find the vertex of a quadratic function.
Answer: The vertex of quadratic function y = x2 + 2x - 2 is given by point (-1, -3)
Let us see how we will use the concept of differentiation in order to find the vertex of a quadratic function.
Explanation:
The point where a quadratic equation has a vertex is the point where dy / dx = 0.
Hence, let us calculate dy / dx for the quadratic function y = x2 + 2x - 2.
On differentiating both sides we get,
dy / dx = 2x + 2.
Now substituting dy / dx = 0, we get
0 = 2x + 2
⇒ x = -1
Substitute x = -1 in y = x2 + 2x - 2
y = x2 + 2x - 2
y = (-1)2 + 2(-1) - 2 = -3
ALTERNATE METHOD:
For quadratic equation y = ax2 + bx + c, the x-coordinate of the vertex is given by -b/2a
For y = x2 + 2x - 2, a = 1, b = 2, c = -2
⇒ x - coordinate of the vertex is -b/2a =. -2/2.1 = -1
Put x = -1 in y = x2 + 2x - 2, we get y = -3
Thus, the coordinates of the vertex are x = -1 and y = -3.
Hence, point (-1, -3) is the vertex of the quadratic equation y = x2 + 2x - 2.
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