Y by coolnick, bobcats4thewin, Adventure10, Mango247
Hi everybody,
The multivariable factor theorem for polynomials as stated in the intermediate algebra book is this: "If f(a,b) is a polynomial and there is a polynomial h(b) in b such that f(h(b),b) = 0 for all b, then we can write f(a,b) = (a-h(b))g(a,b), where g(a,b) is a polynomial."
I couldn't understand the proof provided in the book (namely the part that said, "treat b [a variable] as a constant"), and I would greatly appreciate it if somebody could explain it to me. The proof is included below:
"Taking a closer look at our solution to Problem 9.18, our key step was finding a polynomial h(b) such that f(h(b),b) = 0 for all b. Specifically, we found that if h(b) = b, then f(h(b),b b) = f(b, b) = 0 for all b. This observation guided us to guess that a - h(b) (that is, a - b) is a factor of f(a,b). Viewing f(a, b) as a one-variable polynomial in a and applying the Factor Theorem made it particularly clear that we could write f(a, b) as the product of a - b and another factor. We then found that this other factor is also a polynomial."
I am really confused about how to intuitively (and rigorously if possible without getting to linear algebra or some college mathematics) justify how we can treat b as a constant (and thus viewing the polynomial as a "one-variable polynomial in a"), but in our final statement of the theorem say that both a and b are variables.
I also tried an extensive internet search for multivariable factor theorem for polynomials and nothing accessible came up. Instead, I got a bunch of super complicated mathematics (and some dealing with how get an efficient way for computer programs, etc.).
If anybody is too lazy to explain the solution, would it be possible for someone to provide me a link to a webpage that explains multivariable factor theorem for polynomials?
Thanks so much!
The multivariable factor theorem for polynomials as stated in the intermediate algebra book is this: "If f(a,b) is a polynomial and there is a polynomial h(b) in b such that f(h(b),b) = 0 for all b, then we can write f(a,b) = (a-h(b))g(a,b), where g(a,b) is a polynomial."
I couldn't understand the proof provided in the book (namely the part that said, "treat b [a variable] as a constant"), and I would greatly appreciate it if somebody could explain it to me. The proof is included below:
"Taking a closer look at our solution to Problem 9.18, our key step was finding a polynomial h(b) such that f(h(b),b) = 0 for all b. Specifically, we found that if h(b) = b, then f(h(b),b b) = f(b, b) = 0 for all b. This observation guided us to guess that a - h(b) (that is, a - b) is a factor of f(a,b). Viewing f(a, b) as a one-variable polynomial in a and applying the Factor Theorem made it particularly clear that we could write f(a, b) as the product of a - b and another factor. We then found that this other factor is also a polynomial."
I am really confused about how to intuitively (and rigorously if possible without getting to linear algebra or some college mathematics) justify how we can treat b as a constant (and thus viewing the polynomial as a "one-variable polynomial in a"), but in our final statement of the theorem say that both a and b are variables.
I also tried an extensive internet search for multivariable factor theorem for polynomials and nothing accessible came up. Instead, I got a bunch of super complicated mathematics (and some dealing with how get an efficient way for computer programs, etc.).
If anybody is too lazy to explain the solution, would it be possible for someone to provide me a link to a webpage that explains multivariable factor theorem for polynomials?
Thanks so much!
This post has been edited 1 time. Last edited by theax, May 8, 2011, 8:34 AM