How to set the function

f (x) = 2x ^ 2-2x-2 with x & lt; = 2
F (x) = sqrt (x - 1) at x = 2

Answer 1, Authority 100%

To specify such a function, PieCewise :

f [x_]: = pieecewise [{{2 x ^ 2 - 2 x - 2, x & lt; = 2} , {SQRT [x - 1], 2 & lt; x & lt; = 3}}];