Please assist. I have this Mathematica input DSolve[{ -((2 Derivative[1][h][t])/c) + (2 h[t] \!\(\*SuperscriptBox[\(b\), TagBox[ RowBox[{"(", RowBox[{"1", ",", "0"}], ")"}], Derivative], MultilineFunction->None]\)[x, t])/c == 0 /. b[x, t] -> c/4, h[t]/4 - (b[x, t] h[t])/c == 0 /. b[x, t] -> c/4, (2 Xi[2][t] \!\(\*SuperscriptBox[\(b\), TagBox[ RowBox[{"(", RowBox[{"0", ",", "1"}], ")"}], Derivative], MultilineFunction->None]\)[x, t])/c == 0 /. b[x, t] -> c/4}, {h[t], Xi[2][t]}, {t}] . But I am getting this output: DSolve::deqn: Equation or list of equations expected instead of True in the first argument {-((2 (h^\[Prime])[t])/c)+(2 h[t] (b^(1,0))[x,t])/c==0,True,(2 Xi[2][t] (b^(0,1))[x,t])/c==0}. Help me fix it so that the actual output is a list of equations.s