Question

Interesting problem: I need to find the real zeros of: x^4+3x^3-5x^2-3x+4. I have found that -4, -1 and 1 are one of them. However, I know that by the Descartes rule of sign, there should be at least 2 positive zeros. And 2 and 4 don't seem to work it out. Help please?

Answer 1

hmmm.... I assume you've been using the "rational root test"?

Answer 2

Youve done nothing wrong at all. But be aware you could always have
\[(x-1)^{2}\]and just have it be a repeated root : )

Answer 3

So 1 is the only positive 0?

Answer 4

Yep, it just occurs twice.