How to select a cell from an array when this array is made of functions of a parameter?

Dear all,

Consider an array

A = [a(t) b(t) c(t)].';

I want to select b(t). However, when I enter "A(2)", MatLab returns

a(2)
b(2)
c(2)

instead of

 b(t).

How could we select get b(t) in this case?

Thanks

Answer 1

[Giorgos Papakonstantinou]

You can do

A{2}

or

A{1,2}

Answer 2

[Marlon Saveri Silva]

Thanks. But MatLab returns this error:

   Error using symfun/subsref (line 143)
   Cell indexing and structure indexing are not implemented for symbolic functions.

This is my code:

clear
clc
%%Parameters
l = 12;
h = 0.9;

%%Coord. Systems
syms Alpha(t) Beta(t) Gama(t)
S_1_0=[ 1 0 0 ; 0 cos(Alpha) sin(Alpha) ; 0 -sin(Alpha) cos(Alpha)];
S_2_1=[ cos(Beta) 0 -sin(Beta) ; 0 1 0 ; sin(Beta) 0 cos(Beta)];
S_3_2=[ cos(Gama) sin(Gama) 0 ; -sin(Gama) cos(Gama) 0 ; 0 0 1];
S_3_0=S_3_2*S_2_1*S_1_0

%%Position, Veloc, Acc...
rc=l.*[sin(Gama) -cos(Gama) 0].' + S_3_0*[0 0 h].';
vc=fulldiff(rc,t);
ac=fulldiff(vc,t);
ac_y=ac{2}