I have Maple 11.0. I met a wield problem just now. After I put following expression to the math sheet: (exp(-x)-1)(exp(x)-1)/(exp(-x)-exp(x)) It gave me : ((exp(-x))(exp(x)-1)-1)/(exp(-x)-exp(x)) Obviously it's not what I want when I plot it. it gave me a curve across (0,0.5). But it can easily be calculated the value of this function equals zero when the input is zero.