What is derivative

Gackt247 SG

AHHHHHHHHHHHHHHhhhhhhhhhhhhhhhhhhhhhhhhh... MAAATHHHH Confused HHHHHHHHHHHHHSSSSSSSSSSSSSSsssssssssssss...

dbowie SG

Mad Rolling Eyes Laughing

^tamago^ SG

"dy/dx" means the deriative of y with respect to x. it is a way of expressing this. it's not "dy divided by dx".

so dun keep seperating them into "dy" and "dx". "dx" on its own has no meanings. Laughing

other than x&y. when u start using a third variable, which will come at a later time. now i dun wan to confuse u further, just see above para and dun keep asking for "dx". there's no "dx".

^tamago^ SG

dy/dx is like a function. it is not "dy" divided by "dx". "dx" on its own is not meaningful.

treat dy/dx as a function, much like f(x) = dy/dx = 2x.

dbowie SG

ok... thanks alot
i luv all who help deep deep Embarassed

^tamago^ SG

Embarassed

dbowie SG

A question here .

A function is defined by y= 2x^2/x-1 where x>2.
a).find e` expression for dy/dx.
b).show y=2x^2/x-1 is an increasing function.

^tamago^ SG

a) using quotient rule,
dy/dx = [4x(x-1)-2x²(1)]/(x-1)² = 2x(x-2)/(x-1)²

b) for x>2, (x-2)>0, and thus dy/dx>0.
since dy/dx is always +ve for x>2, y is an increasing function for x>2.

dbowie SG

ok .. my wings are not stiff enough to fly .. but thanks all for letting me know some subtle knowledge about this topic Very Happy

ispyyy SG

Since u want to noe the surface,
in simple english team....

dx means small change of x
dy means small change of y
dx/dy means small change of x / small change of y

y so ma fan leh ???
Coz, every simple fomula, they need to be a prove for it...
Mathematics is the proof for most science...
And there is no term tat describe ever increasing x ... So, they name it as "dx"... Then, can describe everything in the world using mathematics liao...

unclebutcher SG

no more called AO it's now called H1

^tamago^ SG

okies Embarassed

« Previous Page