# function

• Apr 23rd 2012, 04:21 PM
doctorbleachers
function
Given P(x) = x^3 - 3x^2 - 5x
a.evaluate P9x) for each integer value of x from -3 through 5
b. Find all zeros of P(x)
d. Prove that 5 is an upper bound on the zeros of P(x)
• Apr 23rd 2012, 05:02 PM
emakarov
Re: function
a. Do you expect us do this for you?

b. Part (a) gives you one zero; use polynomial long division to get a quadratic equation, which gives you the other two zeros.

c. Estimate the value of square roots from (b). E.g., $\displaystyle \sqrt{29}<\sqrt{36}=6$.
• Apr 24th 2012, 05:46 AM
HallsofIvy
Re: function
Quote:

Originally Posted by doctorbleachers
Given P(x) = x^3 - 3x^2 - 5x
a.evaluate P9x) for each integer value of x from -3 through 5

Do you not understand that this is integer arithmetic? Can you not multiply, add, and subtract integers?

Quote:

b. Find all zeros of P(x)
You can factor an "x" out to P(x) easily, leaving a quadratic term. Do you know the quadratic formula?

Quote:

d. Prove that 5 is an upper bound on the zeros of P(x)
You just need an estimate of the square root that shows up in (b).

(What happened to (c)?)