How to draw the domain of a three variable function?












1












$begingroup$


I have this function



$$f(x,y,z)= sqrt x+sqrt y+sqrt z+ln(4-x²-y²-z²)$$



I know the domain is



$$Df={(x,y,z);x≥0,y≥0,z≥0,x²+y²+z²<4}$$



I need to draw the domain under the form of a sphere, as represented below:
enter image description here



Now my question is , the equation which constructed the general sphere here is x²+y²+z²=4.



But how do i know which parts of the sphere to highlight using the constraints, or else that all x y and z ≥0?



Meaning, which parts of the sphere may correspond to this restrictions? How do i know what to highlight to show the domain ?



EDIT: THIS IS NOT A DUPLICATE. Please do not mark it as such.










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$endgroup$








  • 1




    $begingroup$
    The domain is the intersection of the open ball with the first octant. Isn’t that what you are showing?
    $endgroup$
    – MPW
    Dec 15 '18 at 11:03
















1












$begingroup$


I have this function



$$f(x,y,z)= sqrt x+sqrt y+sqrt z+ln(4-x²-y²-z²)$$



I know the domain is



$$Df={(x,y,z);x≥0,y≥0,z≥0,x²+y²+z²<4}$$



I need to draw the domain under the form of a sphere, as represented below:
enter image description here



Now my question is , the equation which constructed the general sphere here is x²+y²+z²=4.



But how do i know which parts of the sphere to highlight using the constraints, or else that all x y and z ≥0?



Meaning, which parts of the sphere may correspond to this restrictions? How do i know what to highlight to show the domain ?



EDIT: THIS IS NOT A DUPLICATE. Please do not mark it as such.










share|cite|improve this question











$endgroup$








  • 1




    $begingroup$
    The domain is the intersection of the open ball with the first octant. Isn’t that what you are showing?
    $endgroup$
    – MPW
    Dec 15 '18 at 11:03














1












1








1





$begingroup$


I have this function



$$f(x,y,z)= sqrt x+sqrt y+sqrt z+ln(4-x²-y²-z²)$$



I know the domain is



$$Df={(x,y,z);x≥0,y≥0,z≥0,x²+y²+z²<4}$$



I need to draw the domain under the form of a sphere, as represented below:
enter image description here



Now my question is , the equation which constructed the general sphere here is x²+y²+z²=4.



But how do i know which parts of the sphere to highlight using the constraints, or else that all x y and z ≥0?



Meaning, which parts of the sphere may correspond to this restrictions? How do i know what to highlight to show the domain ?



EDIT: THIS IS NOT A DUPLICATE. Please do not mark it as such.










share|cite|improve this question











$endgroup$




I have this function



$$f(x,y,z)= sqrt x+sqrt y+sqrt z+ln(4-x²-y²-z²)$$



I know the domain is



$$Df={(x,y,z);x≥0,y≥0,z≥0,x²+y²+z²<4}$$



I need to draw the domain under the form of a sphere, as represented below:
enter image description here



Now my question is , the equation which constructed the general sphere here is x²+y²+z²=4.



But how do i know which parts of the sphere to highlight using the constraints, or else that all x y and z ≥0?



Meaning, which parts of the sphere may correspond to this restrictions? How do i know what to highlight to show the domain ?



EDIT: THIS IS NOT A DUPLICATE. Please do not mark it as such.







integration multivariable-calculus






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edited Dec 15 '18 at 11:14









gimusi

92.9k84494




92.9k84494










asked Dec 15 '18 at 10:59









BM97BM97

758




758








  • 1




    $begingroup$
    The domain is the intersection of the open ball with the first octant. Isn’t that what you are showing?
    $endgroup$
    – MPW
    Dec 15 '18 at 11:03














  • 1




    $begingroup$
    The domain is the intersection of the open ball with the first octant. Isn’t that what you are showing?
    $endgroup$
    – MPW
    Dec 15 '18 at 11:03








1




1




$begingroup$
The domain is the intersection of the open ball with the first octant. Isn’t that what you are showing?
$endgroup$
– MPW
Dec 15 '18 at 11:03




$begingroup$
The domain is the intersection of the open ball with the first octant. Isn’t that what you are showing?
$endgroup$
– MPW
Dec 15 '18 at 11:03










1 Answer
1






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oldest

votes


















3












$begingroup$

The points





  • $x^2+y^2+z^2 < 4$ are inside the sphere (excluding the points on the surface)


  • $x,y,zge 0$ are those in the first octant


therefore the domain are points in the first octant and inside the sphere.






share|cite|improve this answer









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    1 Answer
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    1 Answer
    1






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    3












    $begingroup$

    The points





    • $x^2+y^2+z^2 < 4$ are inside the sphere (excluding the points on the surface)


    • $x,y,zge 0$ are those in the first octant


    therefore the domain are points in the first octant and inside the sphere.






    share|cite|improve this answer









    $endgroup$


















      3












      $begingroup$

      The points





      • $x^2+y^2+z^2 < 4$ are inside the sphere (excluding the points on the surface)


      • $x,y,zge 0$ are those in the first octant


      therefore the domain are points in the first octant and inside the sphere.






      share|cite|improve this answer









      $endgroup$
















        3












        3








        3





        $begingroup$

        The points





        • $x^2+y^2+z^2 < 4$ are inside the sphere (excluding the points on the surface)


        • $x,y,zge 0$ are those in the first octant


        therefore the domain are points in the first octant and inside the sphere.






        share|cite|improve this answer









        $endgroup$



        The points





        • $x^2+y^2+z^2 < 4$ are inside the sphere (excluding the points on the surface)


        • $x,y,zge 0$ are those in the first octant


        therefore the domain are points in the first octant and inside the sphere.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Dec 15 '18 at 11:06









        gimusigimusi

        92.9k84494




        92.9k84494






























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