0 votes 0 votes Why is $f$ not a function from $R$ to $R$ if $f(x) =1 /x?$ $f(x) = \sqrt{x} ?$ $f(x) =± \sqrt{(x^2+1)}? $ Set Theory & Algebra kenneth-rosen discrete-mathematics set-theory&algebra + – Pooja Khatri asked Apr 9, 2019 Pooja Khatri 240 views answer comment Share Follow See all 0 reply Please log in or register to add a comment.