>p := piecewise(0 <= t and x < 10, R, 10 <= t and t < 20, 0):

changed to be

p := piecewise(0 <= t and t < 10, R, 10 <= t and t < 20, 0):

Help me !!!!

Hey Pro

command >frontend(diff,[A,diff(q[1](t),t)]); workwell but now if A is a matrix then how to do that.

Example:

>B:=<<sin(q[1](t)+q[2](t)),sin(q[1](t)*q[2](t))>|<tan(q[2](t)+q[1](t)),cos(q[2](t)+q[1](t)*q[2](t))>>;
                   
>E:=diff(B,t);

How to canculate diff(E,diff(q[1](t)));

Thanks for your assistantions

Thanks Pro.

I have an other question:

If I have a Matrix having form:

>> restart;
   H := <<cos(x)*(-sin(y)*sin(z)+cos(y)*cos(z)),cos(x)*(sin(y)*cos(z)+cos(y)*sin(z))>| <sin(x)*(-sin(y)*sin(z)+cos(y)*cos(z)), sin(x)*(sin(y)*cos(z)+cos(y)*sin(z))>| 
<sin(y)*cos(z)+cos(y)*sin(z),sin(y)*sin(z)-cos(y)*cos(z)>>;
         
How to transfer it to form following:

<< cos(x)*cos(y+z),cos(z)*sin(y+z)>| sin(x)*cos(y+z),sin(x)*sin(y+z)>| <sin(y+z),-cos(y+z) >>;