Boas's definition of first variation

[sgh1324]

http://www.utdallas.edu/~pervin/ENGR3300/Boaz.pdf

see page 493

he said that first variation of I is

δI = dI/dε * dε

http://www.colorado.edu/ASEN/asen5227_offline/slides/292-334.pdf

but this pdf said (see page 309) that first variation of I is

δI = dI/dε * ε
(y and I commute, α and ε commute)

who is right??

 

[ZapperZ]

http://www.utdallas.edu/~pervin/ENGR3300/Boaz.pdf

see page 493

he said that first variation of I is

δI = dI/dε * dε

http://www.colorado.edu/ASEN/asen5227_offline/slides/292-334.pdf

but this pdf said (see page 309) that first variation of I is

δI = dI/dε * ε
(y and I commute, α and ε commute)

who is right??

First of all, "Boas" is "Mary L. Boas". So it is a "she", not a "he".

Secondly, I don't see anything resembling what you said on the 2nd document on Pg. 309. In fact, the pages leading up to 309, and pages after that are consistent with what was described on Boas's text.

Zz.