Question

If B = {(x,y,z) in R^3 | x^2+y^2 <1}
we define f : R^3 --> R
f(x,y,z) = x^2 +y^2
then B = \(f^{-1}((-\infty, 1))\)
How ? someone explains me, please

Answer 1

@dan815

Answer 2

why isnt it b=f^-1(0,1)

Answer 3

isnt R^3 and R meanins 3D of reals and 1D of real only no complex

Answer 4

hmmm

Answer 5

:D

Answer 6

If B = {(x,y,z) in R^3 | x^2+y^2 <1} ? what does this mean some
poiny x,y,z given x^2+y^2<1?

Answer 7

B = {(x,y,z) in R^3 | x^2+y^2 <1} , this is a cylinder with radius 1

Answer 8

B = {(x,y,z) in R^3 | x^2+y^2 <1} , this is a solid cylinder with radius 1 , with 'dotted edges'

Answer 9

z can vary