You are Here: Home >< Maths

C3 maths question - differentiate to find a stationary point watch

1. Hi, I'm stuck on this question:

Q. The curve with equation y = 1/(x^2 + 1) has a single stationary point A. Find the coordinates of A.

... so I've differentiated the equation which gives dy/dx = (-2x)/(x^2 +1)^2
then I've made that equal to 0, but I'm not sure how you go on to solve it because I don't think you can just multiply up because the 0 would just cancel it out?

Thanks for any help!

(the answer is (0,1) by the way, but idk why)
2. (Original post by daisy18000)
Hi, I'm stuck on this question:

Q. The curve with equation y = 1/(x^2 + 1) has a single stationary point A. Find the coordinates of A.

... so I've differentiated the equation which gives dy/dx = (-2x)/(x^2 +1)^2
then I've made that equal to 0, but I'm not sure how you go on to solve it because I don't think you can just multiply up because the 0 would just cancel it out?

Thanks for any help!

(the answer is (0,1) by the way, but idk why)
The numerator must be 0 for a fraction to be equal to 0. So you're solving 2x=0
3. (Original post by B_9710)
The numerator must be 0 for a fraction to be equal to 0. So you're solving 2x=0
Ahh okay that makes sense. Thank you.
4. Nothing worse than doing all that hard work only to end up with x=0

Related university courses

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 13, 2017
Today on TSR

Edexcel GCSE Maths Unofficial Markscheme

Find out how you've done here

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

Chat with other maths applicants