# Introduction to functions

• Dec 8th 2011, 10:39 AM
moonwoo
Introduction to functions
I need a help here , I can't understand it (Crying)

Q- Which relations define y as a function of x?

1) 3x - y^2 + 4=0

2) y= 4x + 2

(Itwasntme)
• Dec 8th 2011, 10:46 AM
Quacky
Re: Introduction to functions
Quote:

Originally Posted by moonwoo
I need a help here , I can't understand it (Crying)
Q- Which relations define y as a function of x?
1) 3x - y^2 + 4=0
2) y= 4x + 2

If \$\displaystyle y\$ is defined as a function of \$\displaystyle x\$, then for every \$\displaystyle x\$ value, there can only be one \$\displaystyle y\$ value. Try letting \$\displaystyle x=0\$ for both of those and seeing whether this is true.
• Dec 9th 2011, 02:05 AM
moonwoo
Re: Introduction to functions
Can you solve it to me
• Dec 9th 2011, 02:17 AM
emakarov
Re: Introduction to functions
No, the only way though this is for you to understand how to solve this problem. First, you need to understand what a relation and a function are and be able to give examples of relations that are functions as well as relations that are not functions. Then you can follow Quacky's advice.

Feel free to ask any questions.