Show that two MOS transistors connected in parallel with channel widths of W 1 and W 2

Question:

Show that two MOS transistors connected in parallel with channel widths of W₁and W₂and identical channel lengths of L can be modeled as one equivalent MOS transistor whose width is W₁+ W₂and whose length is L, as shown in Fig. 2.76. Assume the transistors are identical except for their channel widths.

Fig. 2.76

M2, W, + W2 L. м, W2 W. L.