How many real roots does this polynomial have? f (x) = 4x^5 + x^3 + 7x - 2 Options: a) 1 b) 3 c) 4 d) 5
I know total number of roots is 5, but how do we find how many of those are real? Please help, thanks.
I know total number of roots is 5, but how do we find how many of those are real? Please help, thanks.
1 Answer
Dec 3, 2017
a)
Explanation:
Given:
f(x)=4x5+x3+7x−2
Note that the pattern of signs of the coefficients is
Note that:
f(−x)=−4x5−x3−7x−2
The pattern of the signs of the coefficients of
So