Powers and Polynomials: intervals where f'(x) >= 1 for f=...

T

tglass

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#55. If f(x) = 4x^3+6x^2-23x+7, find the intervals on which f'(x)>/=1 (Greater than or equal to).

So, f'(x)= 12x^2+12x-23

Now what do I do? Set f'(x) = 1? Then how do I solve it? That doesn't factor, at least, as far as I can tell; so I won't have to neat little expressions that I can set equal to 1 and solve for x.

Thanks in advance,
Tim

PS - Thanks for this wonderful site and your willingness to help. Calculus is killing me!
 
Re: Section 3.1 Powers and Polynomials

This reduces to (x+2)(x-1)?0, hence


+++++++++0-------0+++++++++
-2 1
Ergo (-?,-2]µ[1,?) is the domain where f' (x) ? 1
 
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