Error Propagation in Trigonometric Functions

Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
4 replies · 12K views
H_man
Messages
143
Reaction score
0

Homework Statement



I can't seem to find online how to calculate the error propogated by trigonometric functions.

That is, I know the uncertainty in [tex]\theta[/tex] but am not sure how to deal with it when I apply the tan function.

I am quite okay with how to deal with all the basic functions w.r.t. error analysis, just not the trig ones.


Homework Equations



misc * tan(theta)

The Attempt at a Solution



Searched the internet.
 
Physics news on Phys.org
First thing come to my mind is to use the Tan(A+B) formula..
ps:did you try to differentiate?Tan(A+Delt(A))??
 
Last edited:
what I mean by differentiate is this:
Tan(x+dx)=Tan'(x)dx + tan(x)
Edit:the above formula is derived from the definition of derivation, thus the error would be Tan'(x)dx
 
Last edited:
ziad1985 said:
what I mean by differentiate is this:
Tan(x+dx)=Tan'(x)dx + tan(x)
Edit:the above formula is derived from the definition of derivation, thus the error would be Tan'(x)dx

Minor point: that is true in the limit as dx goes to 0. For non-zero error dx, it is a first order approximation to the error in the function. That's probably what is needed here.
 
Are you asking for propagation of error?
Have a look at here:
http://www.rit.edu/~uphysics/uncertainties/Uncertaintiespart2.html#functions2
 
Last edited by a moderator: