So explain Domain of a function more to me?

Question

So when trying to figure out the domain of the function do I just need to keep pluggin in numbers till I can up with 0? and I i know that number and its inverse wont work?? Im confused please help!

Answer 1

The best way for a beginner to understand domain and range is first to graph the function then study it.

as u get good with it u will find the light.

so, for domains of a function:

eg) f(x)=1/x, we know that x cant be 0 because any number divide 0 is undefined. so in this case, domain:

(-infinity, 0) (0,+infinity) this kind of way to represent the domain is called the "interval notation form" and it's a must know, for the other way to write domain: x =/ 0, lol it means that x do not equals to zero.

so in general, we know that the domain of a equation can't be zero, thus we set the denominator to zero:

eg) f(x) = 1/(2+x), in this case we know the 2 + x cant be zero, so: we set it to equals to zero: 2+x = 0 and then solve for x

x=-2, which means that when x = -2 then function is undefined, therfor the domain of the function is x=/ -2.

the above is the simple domain for fractional(forgot the name of this kind of function, lol).

for function like: y=2x then the domain is just x can be any number.

so from the above u can see that the domain of a function is all the numbers except the numbers which make the function undefined. if you are still undure about this, try to plug in numbers and see if the function make any sense. and you must remanber the rule of the function: for every value of x there is only one value of y. you will understant these things better later on, when u learn the vertical, horizontal and slant asymptote. one piece of advise: find a good graphing calculator(online or buy one urself) graph the function and study it untill u get it,, or else ur gonna suffer in adv. functions

hope this hlp

Answer 2

The domain of a function is best explained with an example. Let's take as an example the function y=3x+2. The domain is the extent of the "x" values that are valid. If this is all we are given, then the domain is infinite (it stretches to negative infinity in one direction and positive infinity in the other). However, if you are told that the domain is from -5 to 5, then it is only valid to plug in numbers for "x" that fall between -5 and 5. This would be something that is given with a problem. The opposite of the domain is then the range, which is the range of values that you would get if you plugged in all the numbers in the domain. So the smallest number we can plug in for "x", -5, would result in a "y" of -13, and the largest, 5, would result in 17. Therefore, the range would be from -13 to 17.

Answer 3

The domain of a function is the set of all argument values for which the function's value is defined. If the function contains a division such that at some argument values(s) a division by zero arises, then those values are not part of the domain. Also, one may wish to have a function defined such that only real values are admissible, and the domain would then include only arguments for which the function value is real. Example: sqrt(x), whose domain includes only zero or positive numbers.

Answer 4

When finding a domain of an equation, its all numbers that will substitute for x and work. To figure this out, u take your equation and do this :

For example,

2x+6>0

2x>-6

x>-3

Then for this equation, the domain is any number greater than -3. And remember, when you divide by a negative number, reverse the greater or less than sign.

Hope this helps!

Answer 5

in fact what he pronounced is its something that once you plug x into it that it gives you a real answer, aka can no longer have 0 interior the denominator and could't be dividing something from 0.