You are Here: Home

# differentiating determinants...

Announcements Posted on
Take our survey to be in with the chance of winning a £50 Amazon voucher or one of 5 x £10 Amazon vouchers 28-05-2016
1. attached.
Attached Files
2. file of porn.doc (41.5 KB, 157 views)
3. maths is no laughing matter.
4. I don't really understand what you want to do. Find the determinant of both those matrices, and then do the derviatives on the left hand side, and you should come out with that identity it gives you. Do you not know how to do a determinant? Or do you not know how to differentiate?
5. (Original post by Worzo)
I don't really understand what you want to do. Find the determinant of both those matrices, and then do the derviatives on the left hand side, and you should come out with that identity it gives you. Do you not know how to do a determinant? Or do you not know how to differentiate?
i just keep going wrong. oh well, i'll keep trying. there's one more i'm stuck on...

a triangle is formed by the lines a_1 x + b_1 y + c_1 = 0, a_2 x + b_2 y + c_2 = 0, a_3 x + b_3 y + c_3 = 0. show the area of the triangle = Δ^2 / 2C_1.C_2.C_3

where C_n denotes the cofactor of c_n
6. For your original question, I find the determinant to be:

yz^2 - zy^2 - xz^2 + zx^2 + xy^2 - yx^2

So finding the partial derivative WRT y, gives

z^2 - 2zy +2xy - x^2

Then finding the partial derivative WRT x gives

2y - 2x

Which you can put back into matrix format.

## Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
2. this can't be left blank
3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
1. Oops, you need to agree to our Ts&Cs to register

Updated: August 11, 2006
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:
Today on TSR

### Don't be a half-term hermit

How to revise this week and still have a life

Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read here first

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams