You are Here: Home >< Maths

# Simple Differentiation Problem Watch

1. I'm having really trouble wrapping my head around differentiation.

Here's one of the first questions on my sheet:

Differentiate from first principles:
y = (x+1)2

Do I use the product rule?
2. Yeah probs
3. nope. the defn of a derivative of f(x) is

where is small

so you know

so just plug it all in and stuff should cancel then take the limit
4. (Original post by chembob)
Yeah probs
not if you have to do it from first principles
5. (Original post by latentcorpse)
nope. the defn of a derivative of f(x) is

where is small

so you know

so just plug it all in and stuff should cancel then take the limit

So I'm replacing all the xs with x+1? Is that what you mean?

EDIT: f(x) will be replaced with (x+1)2, but how will I know what h and f(x+h) is? Is h zero?
6. (Original post by latentcorpse)
not if you have to do it from first principles
What's first principles?
7. Use the chain rule. Try the substitution
8. (Original post by Eljamaispa)
I'm having really trouble wrapping my head around differentiation.

Here's one of the first questions on my sheet:

Differentiate from first principles:
y = (x+1)2

Do I use the product rule?
just use the chain rule

let u = x + 1 ....
9. (Original post by Eljamaispa)
So I'm replacing all the xs with x+1? Is that what you mean?

EDIT: f(x) will be replaced with (x+1)2, but how will I know what h and f(x+h) is? Is h zero?
f(x+h)=(x+h+1)^2 = x^2+h^2+1+2xh+2x+2h
f(x)=(x+1)^2 = x^2+2x+1

f(x+h)-f(x)=h^2+2xh+2h

[f(x+h)-f(x)]/h=h+2x+2

then take the limit and check against the chain rule

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: December 2, 2010
Today on TSR

Find out how.

### Want £10K to start a business?

Discussions on TSR

• Latest
• ## See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams

## Groups associated with this forum:

View associated groups
Discussions on TSR

• Latest
• ## See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.