well, i have a test tomorrow, so if anyone wants to tell me this then it will be appreciated. I have never posted in here hah, this will be sweet if it works. Aight, here it is:

Find a tangential equation to the curve f(x) = x^3 - 6x^2 at its point of inflexion

hm, yeah i haven't been paying attention in class hah. I just don't see how you would find the inflexion point, and then after that how you would find the deriv. of that...hmmm....

-edit- oh yeah, if you are just going to say "you don't know how to do those?", i really don't need that kind of help haha. I've seen it before on this.

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in order to get the inflection point, you have to use the second derivitive, which would end up

f'(x)= 3x^2-12x
f"(x)= 6x-12

being 2 i believe.

So you plug in 2 into the 1st derivitive to get the slope of the tangent line. Then you solve for the y-int etc.

If this is wrong, please post up the right way to do it ahhaa i don't want to go into the AP with flawed knowledge

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all right, where does the 2 come from though?

-edit- thanks, btw.

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"Those womyn that seek equality with men, lack determination."

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you set the f"(x) to zero, and figure out the zero value for the second derivitive. That gets you the inflection point

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ni pour ni contre; ça m'est égal

"The weight of this sad time we must obey,/ Speak what we feel, not what we ought to say./ The oldest hath borne most; we that are young/ Shall never see so much, nor live so long."
King Lear (V.3.300-304)

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oh that's cool...but then you are yielded with the point (2,0)....and that is the inflexion point? So...on a second deriv. graph, where y=0, that is where the inflexion points are? Just want to get it straight.

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Long messages do not equal aggravation of any sort,
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that should always be read in a matter-of-fact tone.

"Those womyn that seek equality with men, lack determination."

"I beseech you, in the bowels of Christ, think it possible you may be wrong."
-Cromwell

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quote:

---

Originally posted by PsychoSnowman
oh that's cool...but then you are yielded with the point (2,0)....and that is the inflexion point? So...on a second deriv. graph, where y=0, that is where the inflexion points are? Just want to get it straight.

---

yea. The second derivitive determines the concavity. When a zero occurs, that means the concavity is switching= infelection point.

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ni pour ni contre; ça m'est égal

"The weight of this sad time we must obey,/ Speak what we feel, not what we ought to say./ The oldest hath borne most; we that are young/ Shall never see so much, nor live so long."
King Lear (V.3.300-304)

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yeeeah, Thank you victor . This is sweet! hah.

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Long messages do not equal aggravation of any sort,
rather they reflect nothing more than a response of insight
that should always be read in a matter-of-fact tone.

"Those womyn that seek equality with men, lack determination."

"I beseech you, in the bowels of Christ, think it possible you may be wrong."
-Cromwell

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np you should go and verify this with another person. I'm good at math, but i am also extremely lazy :huh:

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ni pour ni contre; ça m'est égal

"The weight of this sad time we must obey,/ Speak what we feel, not what we ought to say./ The oldest hath borne most; we that are young/ Shall never see so much, nor live so long."
King Lear (V.3.300-304)

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ok, i have no idea wat ur talkin abt, but the math works out correctly.....if that helps....

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