The domain of a function in interval notation

[nightshade]

1. what is the domain of the function k(y)=1/(2y+1)? Express your answer in interval notation


2.



3. I find that 0.5 is a possibility in this function, but since i have not done functions at school, i do not really know much more of this question.

 

[e^(i Pi)+1=0]

There are generally only two restrictions you have to look for when determining domain. If there is a fraction, the denominator cannot equal 0, and if there is an even numbered radical, the inside cannot be negative.

 

[HallsofIvy]

1. what is the domain of the function k(y)=1/(2y+1)? Express your answer in interval notation


2.



3. I find that 0.5 is a possibility in this function, but since i have not done functions at school, i do not really know much more of this question.

"0.5 is a possibility" for what? It certainly is not the domain because it is not a interval. Are you claiming that 0.5 is in the domain?

 

[nightshade]

So what really is meant by the domain? Is it asking for all possible values of y?

 

[nightshade]

I mean that 0.5 could be y

 

[SammyS]

All possible values for x .

 

[HallsofIvy]

So what really is meant by the domain? Is it asking for all possible values of y?

Good question! You can't solve a problem about the "domain" if you don't know what that word means. Did you consider looking the word up in your textbook?

The "domain" of a function, f(x), is the set of all allowable values lf x. The set of all possible values of the function, y if we have y= f(x), is the "range" of the function.

 

[e^(i Pi)+1=0]

Nightshade,

the domain of f(x)=$\frac{2}{x-1}$ for example is all real numbers except 1, because when x is 1 the denominator goes to 0, and the equation becomes undefined.

This can be notated as D: x≠1 or D:(-∞,1)$\cup$(1,∞)