例如:A=[a2*b [3*a,0] A=sym1(A,2,2,4*b A1三a,2*b] [3*a,4*b] 84=b A2=subs(A1, 'c, b") A2[a,2*c] [3*a,4*j例如：A =[ a, 2*b] [3*a, 0] A1=sym(A,2,2, '4*b') A1 =[ a, 2*b] [3*a, 4*b] A(2,2)='4*b' A3 = [ a, 2*b] [3*a, 4*b] A2=subs(A1, 'c', 'b') A2 =[ a, 2*c] [3*a, 4*c]