How to differentiate this??

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Listen mate all I'm trying to do is help people out and learn myself by doing so. I don't see how leaving a question half answered is helping, what if the OP knew that you had to simplify the answer down to x/2 but didn't know what to do then? Hence quotient/product rule are both acceptable ways of getting the answer.

I don't see how or why there is a problem about that.

Also for the record I did have a glimpse through the forum guidelines and I didn't see anything written there saying "you must leave a question half answered or you will be punished"

Original post by RedGiant

It's not useful to just blatantly state the answer and nothing more, nevertheless use a silly method. They might as well just post all their homework questions otherwise...

lets chill guys, it's only maths! :colondollar:

Reply 21

username3697430

Original post by BTAnonymous

no point doing the whole question otherwise they don't learn anything.

Yh you can use the quotient rule but maths is like coding; it should be simple and clean, free of any unnecessary junk. It also demonstrates whether you can actually see things 'out of the box' instead of 'i see a fraction, use quotient rule'

Yes you are right but for the sake of confusion and the upcoming exams ( 3 months away, for me anyways) we just want to pass a damn paper!

Reply 22

BTAnonymous

Original post by Lord Nutter

Yes you are right but for the sake of confusion and the upcoming exams ( 3 months away, for me anyways) we just want to pass a damn paper!

can't argue that, pretty much me tbh.

Reply 23

username3697430

Original post by RedGiant

It's not useful to just blatantly state the answer and nothing more, nevertheless use a silly method. They might as well just post all their homework questions otherwise...

Chill.

As I said if it gets you the marks in the exam no one really cares how you get the answer just so you understand how to get the answer next time

Reply 24

username3697430

Original post by RedGiant

Good luck you can do this

Yeah good luck to you too - in whatever that may be

Reply 25

RedGiant

Original post by Lord Nutter

Yeah good luck to you too - in whatever that may be

I'm doing A Level maths at the end of year 12, and having learnt A2 differentiation a long time ago, I can safely say you are far more prone to mistakes if you choose to use the quotient rule, rather than simplifying it first. You need to be able to look at a question, and instinctively see that it can be simplified easily, like this one can be. As the poster above said, it's not all about just applying formula because you see a fraction :smile:

Reply 26

username3697430

Original post by RedGiant

Read the previous comments - fully aware that this needed to be simplified I just simply stated a rule that could be used to differentiate this that everyone was familiar with.

Not sure why all of a sudden everyone in the TSR maths department has jumped on this.

Reply 27

Notnek

Original post by Lord Nutter

Not sure why all of a sudden everyone in the TSR maths department has jumped on this.

Probably because you were criticising a perfectly fine hint that was given initially and you wouldn’t back down.

Plus A Level calculus is a lot about finding the quickest method, especially for integration. Its worth pushing home the point that while quotient rule works, it shouldn’t be used for this question because it’s unnecessary and is a waste of time.

It’s equivalent to e.g. solving the equation x^2 - 4 = 0 by using the quadratic forumula. It works but it’s a pointless method and shows that the student is blindingly following methods without thinking.