# Uncertainty for n using calculus

SHAWN JAMES
Homework Statement:
Hi, I need help ASAP with finding the uncertainty of n i've been trying for an hour to figure out how to tackle this question can I please have some guidance as to how to approach the question?!! Thanks in advance.
Relevant Equations:
n=(Sin((Dm + a)/2))/(Sin(a/2))
i'm thinking of differentiating the inside of both sin functions but I'm not sure what to do with the sin. if anything, I'm new to this sort of uncertainty calculation. I have calculated the uncertainty and values for both Dm and a in advance.

## Answers and Replies

I believe you first have to compute ##\frac{dn}{da}## and ##\frac{dn}{d(Dm)}## via a little quotient + chain rule. Then you can take the sum of all of the ##dn##'s.

Homework Helper
Gold Member
Homework Statement:: Hi, I need help ASAP with finding the uncertainty of n I've been trying for an hour to figure out how to tackle this question can I please have some guidance as to how to approach the question?! Thanks in advance.
Relevant Equations:: n=(Sin((Dm + a)/2))/(Sin(a/2))

i'm thinking of differentiating the inside of both sin functions but I'm not sure what to do with the sin. if anything, I'm new to this sort of uncertainty calculation. I have calculated the uncertainty and values for both Dm and a in advance.

Hint: $$df = \frac {\partial f } { \partial x} dx + \frac {\partial f } {\partial y} dy ~+ ... ~$$
where f = f(x,y, ...) and x, y ... are assumed to be independent variables.

etotheipi