Firm I's reaction curve shows how much it will produce as a function of how much it thinks Firm 2 will produce.(The XS, at Q2=0,50 and 75,correspond to the last examples) Firm 2's reaction curve shows its output as a function of how much it thinks Firm 1 will produce. Firm 1's reaction curve shows how much it will produce as a function of how much it thinks Firm 2 will produce. (The XS, at Q2 = 0, 50 and 75, correspond to the last examples) Firm 2's reaction curve shows its output as a function of how much it thinks Firm 1 will produce