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Second Order Derivative Help

Stuck on this problem

(x^5+ 4x^4 -12x^3) / x+6

i basically divided them all by x
x^4 + 4x^3 -12x^2
and then by 6
1/6x^4 + 2/3x^3 -2x^2
i then did dy/dx
4/6x^3 +2x^2 -4x
then did d^2y/dx^2
2x^2 + 4x-4
which is the wrong answer
Original post by AsianG99
Stuck on this problem

(x^5+ 4x^4 -12x^3) / x+6

i basically divided them all by x
x^4 + 4x^3 -12x^2
and then by 6
1/6x^4 + 2/3x^3 -2x^2


Are you saying that x5+4x4−12x3x+6=x4+4x3−12x26=16x4+23x3−2x2\dfrac{x^5+4x^4-12x^3}{x+6} = \dfrac{x^4+4x^3-12x^2}{6} = \dfrac{1}{6}x^4 + \dfrac{2}{3}x^3 - 2x^2 ... ?
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AsianG99
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15
Original post by RDKGames
Are you saying that x5+4x4−12x3x+6=x4+4x3−12x26=16x4+23x3−2x2\dfrac{x^5+4x^4-12x^3}{x+6} = \dfrac{x^4+4x^3-12x^2}{6} = \dfrac{1}{6}x^4 + \dfrac{2}{3}x^3 - 2x^2 ... ?


i guess
Original post by AsianG99
i guess


Well that's not how division works. 61+2=2≠31=3\dfrac{6}{1+2} = 2 \neq \dfrac{3}{1} = 3

You should fully factorise the numerator and notice something before you do any differentiation.
What’s the actual question? Do you have to differentiate that fraction? Or just complete the division?
Reply 5
Avatar for AsianG99
AsianG99
OP
15
Original post by Howie_2114
What’s the actual question? Do you have to differentiate that fraction? Or just complete the division?


Original post by RDKGames
Well that's not how division works. 61+2=2≠31=3\dfrac{6}{1+2} = 2 \neq \dfrac{3}{1} = 3

You should fully factorise the numerator and notice something before you do any differentiation.


find the second order derivative
i've worked it out now
thanks anyways

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