# True or False of convex sets

• Aug 15th 2012, 06:19 PM
rcs
True or False of convex sets
1. the union of two convex sets is a convex sex _______
2. The union of any two convex sets, which have at least two points in common, is a convex set. __________

need your help on this convex sets true or false.

thanks
• Aug 16th 2012, 03:06 AM
emakarov
Re: True or False of convex sets
Try some examples, like filled circles.
• Aug 16th 2012, 03:52 AM
rcs
Re: True or False of convex sets
Quote:

Originally Posted by emakarov
Try some examples, like filled circles.

i cant get it
• Aug 16th 2012, 04:07 AM
emakarov
Re: True or False of convex sets
Attachment 24519

Is the red figure convex? What about the blue one? If you can't answer the first question, you need to study the definition of a convex set and read about examples of sets that are convex and not convex. If this is the case (and note that I only want to say the following if you can't answer the first question), then it is unreasonable to believe that you can solve a problem without knowing the definition, and it would be a waste of time to involve other people in helping you to solve the problem.
• Aug 16th 2012, 06:45 AM
rcs
Re: True or False of convex sets
Quote:

Originally Posted by emakarov
Attachment 24519

Is the red figure convex? What about the blue one? If you can't answer the first question, you need to study the definition of a convex set and read about examples of sets that are convex and not convex. If this is the case (and note that I only want to say the following if you can't answer the first question), then it is unreasonable to believe that you can solve a problem without knowing the definition, and it would be a waste of time to involve other people in helping you to solve the problem.

thank you but among the helpers ... it is not you i would want it be answered :)
• Aug 16th 2012, 06:58 AM
HallsofIvy
Re: True or False of convex sets
I can only conclude from this that you do not know what a convex set is- which makes me wonder why you were given such a problem. A set is "convex" if and only if, given any two points in the set, every point on the line segment between the two points is also in the set. Can you use that, and the pictures emakarov shows, to answer the questions.
• Aug 16th 2012, 09:10 AM
skeeter
Re: True or False of convex sets
Quote:

Originally Posted by rcs
thank you but among the helpers ... it is not you i would want it be answered

Note that you do not get a "choice" of helpers here. emakarov provided sound guidance toward answering your question ... if you choose not to accept it, then I advise you go to another site for seeking help.
• Aug 16th 2012, 06:36 PM
rcs
Re: True or False of convex sets
Quote:

Originally Posted by skeeter
Note that you do not get a "choice" of helpers here. emakarov provided sound guidance toward answering your question ... if you choose not to accept it, then I advise you go to another site for seeking help.

thank you skeeter you are sooo cute :)