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This problem also I really need help on:
Let f(x)=x^4-4x^3-8x^2+5
a) On what interval(s) is f increasing?
b)On what interval(s) is f decreasing?
d) find the local minima of f.
f) lim f(x)=
x->INF
THANKS FOR YOUR HELP! IF YOU COULD ANSWER ALL THESE IT WOULD HELP ME OUT SOO MUCH!
f(x)=x^4-4x^3-8x^2+5
f'(x)=4x^3-12x^2-16x
To find local max/min we solve f'(x)=0 :
4x^3-12x^2-16x=0 -> x^2-3x-4=0 , the solutions are x1=4 & x2=-1.
f is increasing when f'(x)>0 : x>4 or x<-1
f is decreasing when f'(x)<0 : -1<x<4
Lim f(x) = inf
x->inf
Because f(x) is increasing all the time as x goes to inf !
Alon.
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Alon Mandes
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Kind of questions I can answer : Limits, Derivatives, Integration, Implicit functions, continuousity, differentiation ,Extremum problems, Lagrange multipliers, Gradients, Surface integrals, Multi variables functions ,Multi variables Integrals,Complex variables ,Complex functions, Curves, Trajectory integrals & Vector analyse,Divergence,Rotor & word problems. Kind of question I can't answer : Economics,Combinatorics,infinite series & convergence ,Statistics & Probabilities .
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M.A in Mathematics & Bs.c in Electronics.
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