If f′(x)=x4+3+2x3−5x−3f'(x)=\sqrt{x^4+3}+2x^3-5x-3f′(x)=x4+3+2x3−5x−3, then fff has a local maximum at x=x=x=
The graph of fff obtains a local maximum when the value of f′(x)f'(x)f′(x) changes from positive to negative.
Use a graphing calculator to obtain the point:
If , then has a local maximum at