- #1
Saitama
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Homework Statement
For all ##a,b \, \in \, R##, the function ##f(x)=3x^4-4x^3+6x^2+ax+b## has:
a) no extremum
b) exactly one extremum
c) exactly two extremum
d) three extremum
Homework Equations
The Attempt at a Solution
##f'(x)=12x^3-12x^2+12x+a=12x(x^2-x+1)+a##
If a=0, there is one extremum but how what about the other values of a? The given answer is b and using a=0 gives the answer. What if for some other value of a there are more than one extremum.
Any help is appreciated. Thanks!