Why are there 2 (( after disp? Did you count the opening and closing parentheses? As you typed the parentheses, or clicked on one, did you notice the underlines under the matching parenthesis? You should use brackets to concatenate two strings like you're doing. Corrected code:
disp([' (a) tanh(e)=' num2str(tanh(exp(1)))])
I'd use fprintf() instead though.