You are Here: Home >< Maths

# C3 differentation with point of curve help !! watch

1. find the equation of the normal to the curve y=(x+4)/(x^2+1) at the point (0,4)
2. (Original post by yaaasminb)
find the equation of the normal to the curve y=(x+4)/(x^2+1) at the point (0,4)
Differentiate, find the gradient at the point, get the -ve reciprocal of the point, plug the point and the new gradient in your line construction method. Job done.
3. Differentiate the equation of y = (x+4)/(x^2+1) to get the gradient
dy/dx = 1/2x
Because you are finding the normal you will need to reciprocate to get 2x/1
Then substitute in the x value of 0 into the differentiated value.
m = 0
Use y - y(1) = m(x - x(1))
y - 4 = 0(x - 0)
You should get y = 4
4. (Original post by NatKH)
Differentiate the equation of y = (x+4)/(x^2+1) to get the gradient
dy/dx = 1/2x
Because you are finding the normal you will need to reciprocate to get 2x/1
Then substitute in the x value of 0 into the differentiated value.
m = 0
Use y - y(1) = m(x - x(1))
y - 4 = 0(x - 0)
You should get y = 4
1. You're incorrect,
2. Please don't post full solutions.
5. (Original post by RDKGames)
1. You're incorrect,
2. Please don't post full solutions.
6. Have you learnt about the quotient, chain and product rules? Hint: One of those can be applied here Use it and see how far you get. Then post your working here and we can help you out more if needed.

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: November 5, 2017
Today on TSR

### Are exams rubbish?

Is the exam system out of date?

### University open days

• University of Exeter
Wed, 24 Oct '18
Wed, 24 Oct '18
• Northumbria University
Wed, 24 Oct '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