Implicit Differentiation

[frog1944]

Hi,

In 3 Unit am I allowed to use implicit differentiation? I'm aware for the questions they can obviously be done without implicit differentiation (as this is not explicitly taught here), however I find that in some related rates of change questions it can be easier to do using implicit differentiation.

Thanks

[RuiAce]

You're certainly right in that occasionally some are easier with implicit differentiation.

This is another thing that gets debated. That being said, this is a scenario where most teachers would be for it and accept its usage. Implicit differentiation sometimes helps with integration by substitution as well.

[jamonwindeyer]

You're certainly right in that occasionally some are easier with implicit differentiation.

This is another thing that gets debated. That being said, this is a scenario where most teachers would be for it and accept its usage. Implicit differentiation sometimes helps with integration by substitution as well.

Would it be correct to say that you might lose marks for working if your answer is incorrect? That would be my guess at least

[jakesilove]

Would it be correct to say that you might lose marks for working if your answer is incorrect? That would be my guess at least

100%

If your final answer is wrong, and you used a method outside of the 3U curriculum, you are likely to lose marks. Balance that against the fact that implicit calculus might be quicker/save you time. It's your call at the end of the day!

[RuiAce]

Yeah, I'd agree.

Different teachers have different scales of leniency though

[pikachu975]

I think you can definitely use it because IMPLICIT DIFFERENTIATION = chain rule basically which is 2 unit, so why not!

[jamonwindeyer]

I think you can definitely use it because IMPLICIT DIFFERENTIATION = chain rule basically which is 2 unit, so why not!

I'd say it's a fair step above conceptually from applying the chain rule in a basic 2U circumstance - Like, I doubt anyone would know how to do it without being taught it explicitly. Which is why you've got to be careful - It's an atypical/extended method, and would only really be useful in a few circumstances I can think of

[frog1944]

Ok, thanks very much guys. I'll be careful if I use it.

[Wales]

Both a friend and I were both taught Implicit differentiation at 3U tutoring. Only ever seen it being used in 1 3U paper but still. I actually thought it was a 3U technique haha. Guess I should ask my teacher to be sure.

[RuiAce]

Both a friend and I were both taught Implicit differentiation at 3U tutoring. Only ever seen it being used in 1 3U paper but still. I actually thought it was a 3U technique haha. Guess I should ask my teacher to be sure.

It's a 4U technique. Your teacher knows.

From memory she's one of them that's happy with its usage in 3U.

[Wales]

It's a 4U technique. Your teacher knows.

From memory she's one of them that's happy with its usage in 3U.

How about BOSTES/NCEA? Has there ever been a need for it's use in a 3U HSC Paper?

[RuiAce]

There has never been a need for it. It only makes things more convenient, as implied in the original post

[pikachu975]

I'd say it's a fair step above conceptually from applying the chain rule in a basic 2U circumstance - Like, I doubt anyone would know how to do it without being taught it explicitly. Which is why you've got to be careful - It's an atypical/extended method, and would only really be useful in a few circumstances I can think of

I feel like it's extremely useful when you have like v^2 in terms of t and you gotta find acceleration and it'd be wayyy easier to differentiate implicitly rather than square root then differentiate etc.

[RuiAce]

I feel like it's extremely useful when you have like v^2 in terms of t and you gotta find acceleration and it'd be wayyy easier to differentiate implicitly rather than square root then differentiate etc.

I have never seen this kind of problem appear in the scope of Extension 1.