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**UWstudent** The initial price of *buzz.com* stock is $20 per share. After 20 days the stock price is $30 per share and after 40 days the price is $35 per share. Assume that while the price of the stock is not zero it can be modeled by a quadratic function.Find the multipart function *s*(*t*) giving the stock price after *t* days.

{s(t) = (quadratic function) when 0≤t≤125 and t>125

--For this part I tried to form a quadratic equation out of the point (0,20) (20,30) (40,35). I know the stock price cannot equal zero, but it is unclear to me how/why it needs to be a parametric equation. the price must equal zero at 125 days?

I think once I understand how to set up the equation I can do the other parts. but here they are:

(a) If you buy 1000 shares after 30 days, what is the cost?

(b) To maximize profit, when should you sell shares?

How much will the profit be on your 1000 shares purchased in (a)?