Calculus question....

[Damo17]

Differentiate with respect to x:


Tried it but unsure of what to let u equal.

[ell]

Let , so then

[shinny]

What do you mean what to let 'u' equal? Hopefully you're not confusing diff with anti-diff here...normally I'd do this without having to define anything and just go straight for the chain rule in 1 line, but if you must, let cos(x+1) be u then and then chain rule it.

[Collin Li]

Let



(You can use chain rule to find this, if you can't see it)

[Damo17]

thanks all, i got it now.

[Damo17]

What do you mean what to let 'u' equal? Hopefully you're not confusing diff with anti-diff here...normally I'd do this without having to define anything and just go straight for the chain rule in 1 line, but if you must, let cos(x+1) be u then and then chain rule it.

I would normally do that but my teacher has given us questions that we have to use the long way and questions to do it the quick way.

[Damo17]

Another question using the product rule.

Differentiate:


I can do most of it but hit a road block.

[Collin Li]

Let and

and

[Damo17]

^
Thanks coblin,
I forgot to change the 4x to 2x!!

[Synesthetic]

What do you mean what to let 'u' equal? Hopefully you're not confusing diff with anti-diff here...normally I'd do this without having to define anything and just go straight for the chain rule in 1 line, but if you must, let cos(x+1) be u then and then chain rule it.

Integration by u-substitution isn't in Methods anyway [as in the linear substitution form, which is in Specialist], whereas chain rule by this technique is in almost all the textbooks. (And I agree, I don't think the latter helps much!)

[shinny]

Ahah yeh didn't realise it was in the methods board; woops.

[Mao]

Damo still need to be careful about it though, assuming if he is doing Spesh and MUEP Math next year =)

you should learn to do the Chain Rule without using a u-substitution. Whilst it doesn't change the answer, it can over-complicate things and make your workings unnecessarily big, it is almost necessary when you are in spesh and uni-math unless you can fit a lot of workings in a small space.

[Damo17]

Damo still need to be careful about it though, assuming if he is doing Spesh and MUEP Math next year =)

you should learn to do the Chain Rule without using a u-substitution. Whilst it doesn't change the answer, it can over-complicate things and make your workings unnecessarily big, it is almost necessary when you are in spesh and uni-math unless you can fit a lot of workings in a small space.

Thanks for the advice Mao.

I can do most question without u-substitution but there are a few that I struggle to do it that way so I try it the long way.

[Damo17]

Another one I'm stuck on.

Differentiate:


This is what I have done so far:











     

     

I think it is correct so far but I don't know where to go from here. Any help/explanation would be greatly appreciated.

[ed_saifa]

Take out a common factor