Thursday, October 8, 2009

2.3: Polynomial Equations - Period 3/4

Polynomial Equations
Today we quickly learned how to turn polynomial functions into polynomial equations. Using the example from the class, V(x) = 9x^3 + 60x^2 + 249x with the given volume of 2532 cm^3, we find the maximum thickness of a block of ice.

First, we set up the equation:
V = 2532
V(x) = 9x^3 + 60x^2 + 249x

2532 =
9x^3 + 60x^2 + 249x
0 =
9x^3 + 60x^2 + 249x - 2532

Next, we use the factor theorem to determine if there are any integral roots:
  • we fine that f(4) = 0
  • we use either synthetic division or long division.
We end up with the result 9x^2 + 96x + 633 with 0 remainders.
0 = (x-4)(9x^2 + 96x + 633)














Since it is not a real root it is, therefore, the max thickness the block can be is 4 cm.

Comment if there are any errors within the post.



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