2 The region bounded by the \(x\)-axis, the \(y\)-axis, the line \(x = \ln 3\), and the curve \(y = \mathrm { e } ^ { - x }\) for \(0 \leqslant x \leqslant \ln 3\), is occupied by a uniform lamina. Find, in an exact form, the coordinates of the centre of mass of this lamina.