Calling all Math Wizards

[Wing Zero]

I really have no clue what is going on in that red box. Especially the very beginning of the numerator.

 

[Static]

I think its funny how wang is trying to make people think he's not good at math.

 

[Ntrik_]

this is so easy

jus open ur txtbook, look at the section that explains how u do derivatives with complex fractions, read the examples, apply the knowledge onto that question

then solve the problem

 

[Johnny]

That's just quotient rule. Derivative of the top function times the bottom function (top function, by power rule, goes from ^(1/2) to ^(-1/2), that's why it is on the top of the x(x^3-1) (the x comes from a chain rule of the top function). The 2nd half of the quotient rule is you subtract the derivative of the bottom multiplied by the top function. This is all over the bottom function squared.

They then simplify by multiplying by (x^2+4)^(1/2)/(x^2+4)^(1/2). And then they multiply and combine like terms.

 

[Wing Zero]

ololol forgot the 1/2*sqrt(x) thing. but where did that x come from in x(x^3 -1)

 

[Johnny]

The only thing I can't figure out is why it's an x and not a 2x. It should come from the chain rule with the x^2+4 that is inside the radical.

 

[Wing Zero]

the 2's cancel out i think

i can get to the first part but i cant move to the second
why the square root part of the problem in the bottem

 

[CelestialBadger]

if you're not x42 get the fuck out of this thread. this is his time to shine

 

[Jim Morrison]

sup guys i hurd u need math helps?

 

[EEX_ca_aok]

They multiplied the top and bottom by the square root part to cancel the fractions in the top half of the big fraction, thus making life slightly less painful. It also cancels the square root in the second term on top.