Calc III

  • #1

Homework Statement



Write the equation of the sphere whose diameter has endpoints at (-1,1,-3) and (3,-1,2).



Homework Equations





The Attempt at a Solution



(x-x1)2+ (y-y1)2+ (z-z1)2= r2

the center of the sphere is : (1,0,-1/2)
r= [tex]\sqrt{}5/4[/tex]

then the equation is: (x-1)2+(y-0)2+(z+1/2)2=5/4

Please someone check my answer and if I am not right, help me to solve it.
 

Answers and Replies

  • #2
tiny-tim
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the center of the sphere is : (1,0,-1/2)
r= [tex]\sqrt{}5/4[/tex]

Hi mamma_mia66! :smile:

Centre is right. :biggrin:

But r is wrong. :cry:

(you've calculated the distance from the centre to the origin! :wink:)
 
  • #3
I am not sure that I know how to find the r ???? too old to remember it after so many years not being in school.
 
  • #4
tiny-tim
Science Advisor
Homework Helper
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Yes you do! :biggrin:

they've given you a diameter:wink:
 
  • #5
r= sq. rt. (3-1)2+ (1-0)2+(2-1/2)2= 21/4
 
Last edited:

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