Help Calculate Errors: Lambda & n Uncertainty on 'n2

[Owen-]

Homework Statement

I need to find the uncertainty on "n2" I have the uncertainty on lambda, n1 is not a variable - its 2, R is a constant. Only things that have errors are lambda and n

Homework Equations

The Attempt at a Solution

Tried working out using calculus, but every time I do it I get a different aswer

Im trying to use errorλ= error n * dλ/dn

But I can't get dy/dn - I've been up all night - don't judge me


Any help would be seriously SERIOUSLY helpful!

Thanks!
Owen.

 

[zzzoak]

I think that the error is

$$\frac{d \lambda}{\lambda}=2 \frac{n_1^2 \; dn_2}{n_2 \: |n_2^2-n_1^2|}$$

 

[Owen-]

sorry - didnt get a chance to thank you for that - was too busy rushing out to get the project handed in - thanks a lot! :)