Finding Domain & Range of $$y=\sqrt{x^2+y^2}$$

In summary, the function $y=\sqrt{x^2+y^2}$ has a domain of all real numbers and a range of all non-negative real numbers. The locus of points satisfying the equation is the non-negative y-axis, and an alternative way to express the equation is $y=|y|$. The x-axis can also be expressed in a similar way as $x=\sqrt{x^2+y^2}$, but it only represents the non-negative y-axis.
  • #1
Maged Saeed
123
3
I was thinking about a function whose domain and range are absolutely one point , then I'm stuck in finding the domain and range of the following function .. could anyone help

$$y=\sqrt{x^2+y^2}$$
 
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  • #2
Well, first we see that:

\(\displaystyle 0\le y\)

Square both sides...what do you find?
 
  • #3
Yeah I got it now ..

You mean that y is greater than zero so the range is from zero to infinity

x is all real number !

right ?
 
  • #4
Maged Saeed said:
Yeah I got it now ..

You mean that y is greater than zero so the range is from zero to infinity

x is all real number !

right ?

$y$ and be any non-negative real number, including zero. Squaring, we obtain:

\(\displaystyle y^2=x^2+y^2\)

What does this tell you about $x$?
 
  • #5
MarkFL said:
$y$ and be any non-negative real number, including zero. Squaring, we obtain:

\(\displaystyle y^2=x^2+y^2\)

What does this tell you about $x$?

This tell me that x can be any real number and must be zero in order to solve the equation.Thanks Mr MarkFL
 
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  • #6
Well, it does tell you $x=0$...and so the original equation becomes:

\(\displaystyle y=\sqrt{y^2}=|y|\)

So, what is the locus of points satisfying the equation?
 
  • #7
It will be the equation of the y-axis since x is always zero
the points are (0,y)

I found that it is an alternative way to express the equation of the axis.

Similarly the equation of the x-axis in this way is

$$x=\sqrt{x^2+y^2}$$
 
Last edited:
  • #8
Well, it's only the non-negative $y$-axis, isn't it?
 
  • #9
Yes, It is
 

Related to Finding Domain & Range of $$y=\sqrt{x^2+y^2}$$

1. What is the definition of a domain and range?

A domain is the set of all possible input values for a function, while a range is the set of all possible output values for a function.

2. How do I find the domain and range of a given function?

To find the domain and range of a function, we need to look at the restrictions on the input values and the possible output values. For a square root function like y=√(x^2+y^2), the radicand (the expression under the square root) must be greater than or equal to 0, so the domain is all real numbers. The range depends on the value of y, but it will always be greater than or equal to 0 since the square root of a non-negative number is always non-negative.

3. Can the domain and range of a function be infinite?

Yes, the domain and range of a function can be infinite as long as there are no restrictions on the input or output values. In the case of y=√(x^2+y^2), the domain and range are both infinite since there are no restrictions on the values of x and y.

4. How can I graph a function to determine its domain and range?

To graph a function and determine its domain and range, we can plot several points and connect them to create a curve. The domain and range can then be determined by looking at the x and y values of the plot. For y=√(x^2+y^2), we can plot points with different values of x and y to see that the curve extends infinitely in all directions, indicating an infinite domain and range.

5. What is the significance of finding the domain and range of a function?

Finding the domain and range of a function is important because it helps us understand the behavior of the function. It also allows us to determine the set of valid input and output values, which can be useful in solving equations and making predictions about the function. In some cases, the domain and range can also provide insights into the symmetry and shape of a function.

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