Help with inequalities

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Feb 18th 2010, 05:24 AM
jhbguy

Help with inequalities

I just got a whole lot of questions to do for tomorrow and i really need help, iv managed to do the first bit of inequalities but im still stuck on a few, all we solve the inequality in terms of intervals and illustrate it on a number line:
33) x^3 - x^2 <=0
35) x^3 > x

im really stuck on these 2, i didnt do maths in high school so this is all new to me and im forced to do maths for my computer science degree
Feb 18th 2010, 05:30 AM
Krizalid

Quote:

Originally Posted by jhbguy

33) x^3 - x^2 <=0
35) x^3 > x

for the first one $x^3-x^2=x^2(x-1),$ since $x^2\ge0$ we require that $x-1\le0,$ namely $x\le1.$

for the second one $x^3-x=x(x+1)(x-1)>0,$ so here you need to study the following sets: $(-\infty,-1),$ $(-1,0),$ $(0,1)$ and $(1,\infty).$

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