Differentiation rules (1 Viewer)

[Joshmosh2]

For the main differentiation rules (product, quotient etc) are you expected to expand and simplify to its smallest form?
Just finished the product rule exercises and that was the most tedious thing i've ever done..

 

[braintic]

You will soon be equating the derivative to zero. So you need to be able to fully factorise the answer.

 

[lilcutetricker]

most questions in exam will ask you to leave it in most simplest. Sorry bro.

 

[cub3root]

most questions in exam will ask you to leave it in most simplest. Sorry bro.

actually; as long as you've diff'ed it, then you can get full marks. Don't need to simplify/mess around with it

 

[lilcutetricker]

actually; as long as you've diff'ed it, then you can get full marks. Don't need to simplify/mess around with it

Well the more difficult questions will ask you to leave it in any form but I've seen people not fully simplifying for and lost 1 or 2 marks out of a 4 or 5 mark question in my half yearlies.

 

[cub3root]

Well the more difficult questions will ask you to leave it in any form but I've seen people not fully simplifying for and lost 1 or 2 marks out of a 4 or 5 mark question in my half yearlies.

4/5 marks for a simple diff is not "normal". I am talking about the ones in the HSC Q's11-13 (formerly Q's 2-3) where they are worth only 2 or 3 marks at the max.

for example: find f'(x) if f(x) = xe^x [2 marks]

you could write:

f'(x) = e^x + xe^x

OR

f'(x) = e^x(1+x)

I would give full marks to either answer if one of my students did that.

even if they made a "small mistake" for example

find f'(x) if f(x) = xe^x

f'(x) = e^x + xe^x.........(1)

f'(x) = e^x(2+x).........(2)

i would still give them full marks and give a CFPA at line 1

 

[panda15]

actually; as long as you've diff'ed it, then you can get full marks. Don't need to simplify/mess around with it

This. My old teacher has marked 2U papers for years, and he said they don't pay marks for simplifying. Unless the question says "simplify", just differentiate it and move on. It's a waste of time simplifying it.

 

[cub3root]

This. My old teacher has marked 2U papers for years, and he said they don't pay marks for simplifying. Unless the question says "simplify", just differentiate it and move on. It's a waste of time simplifying it.

yes what panda15 said. there is no requirement to simplify it unless the question specifically asks you to like most Q11)a) (formerly Q1)a)) where you have to simplify to 3 sig fig, etc etc.

It does look much more aesthetically pleasing having the final result in simplest form but there is no requirement to do this

 

[braintic]

This. My old teacher has marked 2U papers for years, and he said they don't pay marks for simplifying. Unless the question says "simplify", just differentiate it and move on. It's a waste of time simplifying it.

"They" being HSC markers.
There is no guarantee that teachers at his school will mark in this way, and my experience says most don't.
OP should be asking his teacher. I feel uncomfortable giving students minimalist advice based on what happens in the HSC, when there is a good chance that this will cost them marks in school assessments.