# sqrt(x) is sqare root, x^(1/2); # sqrt(x_) := If(x==1, 1, If(x== -1, i, If(not(isnumber(x)), x^(1/2) ))); sqrt(1/x_):=1/sqrt(x); sqrt(x_^2):=x*csgn(x); sqrt(0.25):=1/2; sqrt(-1):=i; sqrt(1):=1; sqrt(4):=2; sqrt(9):=3; sqrt(16):=4; sqrt(25):=5; sqrt(36):=6; sqrt(49):=7; sqrt(64):=8; sqrt(81):=9;