What is the difference between factoring with integer coefficients and factoring with real coefficients? Although the answer to this question probably sounds pretty obvious, I'm not sure how my answer changes in the question below.
If I was to factor $$3x^5-x^4-3x^3+x^2-6x+2$$
with integer coefficients, the answer is $$(3x-1)(x^2-2)(x^2+1)$$
How does my answer change if I am factoring with real (not necessarily integer) coefficients?
Best Answer
Factoring over the integers, we see that $$3x^5 - x^4 - 3x^3 + x^2 - 6x + 2 = (3x - 1)(x^2 - 2)(x^2 + 1).$$ Factoring over the reals, we see that $$3x^5 - x^4 - 3x^3 + x^2 - 6x + 2 = 3(x - 1/3)(x - \sqrt{2})(x + \sqrt{2})(x^2 + 1).$$ Factoring over the complex numbers, we have $$3x^5 - x^4 - 3x^3 + x^2 - 6x + 2 = 3(x - 1/3)(x - \sqrt{2})(x + \sqrt{2})(x + i)(x - i).$$