Increasing curve question (1 Viewer)

[Smilebuffalo]

P(x) = 8x^3 -12x^2 + 6x + 13.

For what values of x is P(x) increasing?

 

[Bdogz]

When the first derivitive >0

 

[Smilebuffalo]

yea i know but for what value(s) of x?

 

[addikaye03]

P(x) = 8x^3 -12x^2 + 6x + 13.

For what values of x is P(x) increasing?

P'(x)=24x^2-24x+6

P'(x)>0 for increasing values

24x^2-24x+6>0

4x^2-6x+1>0

x=[6+-sqrt(36-16)]/8 (quadratic formula)

=(6+-2rt5)/8

So they are the values (sorry i dont have a calculator in hand)

then set up on a number line:

<-------A-------B------->

Test points for each section ie. <A, A<x<B, and >B and see where the inequality holds true.

That's your answer