How do you graph #F(x,y)=sqrt(x^2+y^2-1)+ln(4-x^2-y^2)#?

1 Answer
Mar 26, 2015

Hello,

  • Let #Sigma# the surface of your function #F# : it's a surface of revolution because #F(x,y) = f(r)# where #r = sqrt(x^2+y^2)#. Precisely, #f(r) = sqrt(r^2-1) + ln(4-r^2)#

  • First, plot the curve of #f : r \mapsto sqrt(r^2 -1) + ln(4-r^2)#. You get

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  • Now, turn this curve around #z#-axes in 3D-space. You get the surface #Sigma#

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