Question

Ivan purchased stock in a company at an initial price of $8 per share. The share value reached $18 after 10 days and then began to decrease. He found that the stock’s value over time was best modeled with a quadratic function. Which graph best represents his model of the relationship between stock value and time?

Answer 1

The quadratic equation that best represents his model of the relationship between stock value and time is given by:

$y = -0.0976(x - 10)^2 + 18, x \geq 0$

The graph is given at the end of the answer.

What is the equation of a parabola given it’s vertex?

The equation of a quadratic function, of vertex (h,k), is given by:

$y = a(x - h)^2 + k$

In which a is the leading coefficient.

In this problem, the maximum value was a share value of $18 after 10 days, hence the vertex is:

(h,k) = (10,18).

Thus:

$y = a(x - 10)^2 + 18$

Since the initial price was of $8 per share, we have that:

$8 = a(0 - 10)^2 + 18$

$-82a = 8$

$a = -\frac{8}{82}$

$a = -0.0976$

Hence the equation is:

$y = -0.0976(x - 10)^2 + 18, x \geq 0$

At the end of the answer, the sketch of the graph is given.

More can be learned about quadratic equations at brainly.com/question/24737967