You are Here: Home >< Maths

# FP1 2nd Order DE's (by sub) watch

Announcements
1. Just a quick question:

Looking at the explanation of:

Given that:

where u is a function of x.

How do they do this step:

?

Thanks
2. The

Think about the chain rule and the fact that implicit differentiation is a result of the chain rule.
3. I asked this exact question on another site a couple of days ago...

From product rule, essentially its obviously e^u(dy/dx)+ e^u[d/du(dy/dx)]

the d/du(dy/dx) can be written as d/dx(dy/dx)(dx/du) which then gives you d2y/dx2(dx/du) from the chain rule
4. I asked this question too right here. They've used the chain rule without really stating it-- not very good for a 'worked example.'
5. Yes i told Nicholas this over Msn he said he understood it.

Bad bad example, however the equation is slightly challenging in the fact that it makes you think abit outside the box ive never had to anything like this with dy/dx.

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: October 17, 2006
Today on TSR

And I hate it

### University open days

• Heriot-Watt University
School of Textiles and Design Undergraduate
Fri, 16 Nov '18
• University of Roehampton
Sat, 17 Nov '18
• Edge Hill University
Faculty of Health and Social Care Undergraduate
Sat, 17 Nov '18
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