The Math Forum

Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Math Forum » Discussions » Math Topics » discretemath

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

Topic: Functions need Help
Replies: 3   Last Post: Apr 9, 2012 6:31 PM

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]
Ben Brink

Posts: 201
From: Rosenberg, TX
Registered: 11/11/06
RE: Functions need Help
Posted: Apr 5, 2012 11:17 AM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply
att1.html (1.0 K)

Without additional conditions, I don't think it's true. Let A and B both denote the nonnegative real numbers. Define f mapping A to B by
f(x) = sqrt(x), where "sqrt" denotes the square root.
Now if x < y, f(x) - f(y) is not in B. Hope this helps.

> Date: Thu, 5 Apr 2012 07:50:10 -0400
> From:
> To:
> Subject: Functions need Help
> Let f : A ? B be a function, with S, T ? A. Show that f[S] ? f[T] ? f[S ? T]. Give an example where equality fails.
> I dont understand how to start this.

Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© The Math Forum at NCTM 1994-2018. All Rights Reserved.