Is this a bad habit? (1 Viewer)

[HeroWise]

I have read that Delta x on Delta y is different to dx/dy

But im SOOO used to delta x/ delta y that when i do any questions i put it in. Is this technically wrong? or should i try to change this habit?

 

[Drongoski]

Didn't I already point out to you a few months ago that the 2 things are distinct. It is not just your bad habit (few people have this "habit") but it is simply incorrect.

And stop using delta y/delta x when you mean't dy/dx. Maybe most teachers and markers would overlook the difference; result is you think they are the same thing.

 

[HeroWise]

i do remember u pointing it out, and thanks a lot for it again,

but like i have heard in 4u the teacher basically forces you to use delta y on delta x

In school we just started basic integration as we are starting year 11 prelims next term. He has done dy/dx. I have seen that his methods pf teaching are actually good and an hsc marker, he do gives the expectations and standards for the hsc.
I addressed this because you told me off last time ahah
Im like in an inner battle rn
And again, when i started calculus, i used deltas so its like ingrained. need to really change it

and again thanks Drongoski

 

[fan96]

but like i have heard in 4u the teacher basically forces you to use delta y on delta x

Not true. If your teacher makes you do it then they are wrong.

In particular,



(as the Cambridge textbook states when introducing the derivative)

So the two are subtly different things - is a change in , but is specifically an infinitesimal change in .

 

[Drongoski]

i do remember u pointing it out, and thanks a lot for it again,

but like i have heard in 4u the teacher basically forces you to use delta y on delta x

In school we just started basic integration as we are starting year 11 prelims next term. He has done dy/dx. I have seen that his methods pf teaching are actually good and an hsc marker, he do gives the expectations and standards for the hsc.
I addressed this because you told me off last time ahah
Im like in an inner battle rn
And again, when i started calculus, i used deltas so its like ingrained. need to really change it

and again thanks Drongoski .

Please report such teachers to me for a public dressing-down.

 

[Drongoski]

Not true. If your teacher makes you do it then they are wrong.

In particular,



(as the Cambridge textbook states when introducing the derivative)

So the two are subtly different things - is a change in , but is specifically an infinitesimal change in .

What is "infinitesimal" (used a lot in textbooks in the 50's and prior) and how does it help clarify things? dy/dx is just the notation for the limit when this limit exists. This limit you now call the "derivative"; at one time it was also called the "differential coefficient"