Register to reply

Identically zero

by joshmccraney
Tags: identically
Share this thread:
joshmccraney
#1
May25-14, 03:48 PM
P: 346
hey pf!

when would you use "identically zero" as opposed to simple "zero". example: f is identically zero on interval a to b. or, f is zero on interval a to b.

why do we ever use identically? it seems superfluous...

thanks!
Phys.Org News Partner Mathematics news on Phys.org
Heat distributions help researchers to understand curved space
Professor quantifies how 'one thing leads to another'
Team announces construction of a formal computer-verified proof of the Kepler conjecture
micromass
#2
May25-14, 04:04 PM
Mentor
micromass's Avatar
P: 18,293
It's because the statement "##f## is zero on the interval ##[a,b]##", might be interpreted as there is a ##c\in [a,b]## such that ##f(c) = 0##. I know that the proper language should be that "##f## has a zero", rather than what I wrote. But writers want to be clear and write that it is identically zero to avoid misunderstandings.
SteamKing
#3
May25-14, 10:27 PM
Emeritus
Sci Advisor
HW Helper
Thanks
PF Gold
P: 6,532
'Identically' is sometimes used for emphasis.

Of course, sin[itex]^{2}[/itex]θ + cos[itex]^{2}[/itex]θ is identically 1.

joshmccraney
#4
May26-14, 09:31 PM
P: 346
Identically zero

thanks to you both!


Register to reply

Related Discussions
A theorem about identically zero potential function Calculus 5
Showing an analytic function is identically zero Calculus & Beyond Homework 3
X and Y identically distributed implies E(X) = E(Y) and var(X) = var(Y) Calculus & Beyond Homework 4
Independent identically distributed random variables Set Theory, Logic, Probability, Statistics 4
Vanishes identically General Math 1