How to take derivative of a function

hi, please can you help me to find derivative of the following .

x = t; y = sin(t); 
z =cos(t) 
%  for the range-5 <= t <= +5

I tried to use diff function but it doesnt work.Any suggestions please

Answer 1

[Star Strider]

If you have the Symbolic Math Toolbox, use that version of diff (link).