+118725 Sun 20/7/14
♬ ♬ ♬ MELODY ♬ ♬
1) Rosala's Wrap - Thanks Rosala, we really enjoy these. I love the Goa waterfall! And the fun pics as well!
http://web2.0calc.com/questions/lets-end-the-day-with-a-laugh_5#r3
2) Calculus - Interesting problem which uses the chain rule.
http://web2.0calc.com/questions/a-street-light-is-on-top-of-a-6m-pole
3) Thankyou Rosala 
http://web2.0calc.com/questions/is-their-another-forum-like-this
+118725 @@ End of Day Wrap :Sat19/7/14 Sydney, Australia Time 10:30 pm ♬ 
It was a quite Fri/Sat today but as always there were some good answers. These were provided by CPhill, Alan, Rosala, NinjaDevo, Zegroes, Kitty3 and GoldenLeaf. Thanks all.
My new avitar has created some interest. She is Lady (Queen) Guinevere of Camelot from the Brittish TV series "Merlin". Arthur was the Legendary King of Camelot. I was given the title of Queen Guinevere by another member, Morgan Tud. Morgan Tud was the chief Physician to the royal court of Camelot.
http://www.quest4camelot.com/legend/history.html
https://www.google.com.au/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=TV+series+Merlin
I have not settled on any permanent avitar, I will swap to another at some point in time.
----------------------------------------------------------------------
I only really noted one interesting thread tonight:
1) This higher level one looks interesting. (Thanks Alan)
That is it for tonight. Thanks everyone. Enjoy your weekend.
♬ ♬ MELODY ♬ ♬
♬ ♬ LADY GUINEVERE, QUEEN OF CAMELOT ♬ ♬
+118725 Umm yes,
every x value only has one y value.
The graph has to pass the straight line test. This means that any vertical line will never cut the graph more than once.
This might help you.
http://www.mathsisfun.com/sets/function.html
Sometimes restrictions a placed on relations so that they become functions.
eg
$${{\mathtt{x}}}^{{\mathtt{2}}}{\mathtt{\,\small\textbf+\,}}{{\mathtt{y}}}^{{\mathtt{2}}} = {\mathtt{16}}$$ Is a circle, radius 4 and centre(0,0)
This IS a relation, because there is a relationship between x and y.
When x=0 y can be 4 or -4, Since there are 2 possible values of y, this is NOT A FUNCTION.
However, if you restrict the range and say $$0\le y \le 1$$ it then becomes a FUNCTION
NOTE:
All functions are relations but not all relations are functions.
To make this easier to understand I will show a comparison.
All squares are rectangles but not all rectangles are squares.
All roses are flowers but not all flowers are roses.
All terriers are dogs but not all dogs are terriers.
