Does #f(x) = x^7+2x^6+3x^5+4x^4+5x^3+6x^2+7x+8# have at least one real root?

1 Answer
May 19, 2017

Yes

Explanation:

Any polynomial function of odd degree with real coefficients has at least one real zero, by the intermediate value theorem.

Given:

#f(x) = x^7+2x^6+3x^5+4x^4+5x^3+6x^2+7x+8#

We find:

#f(-2) = -128+128-96+64-40+24-14+8 = -54#

#f(0) = 8#

So #f(x)# has some zero in #(-2, 0)#