显然 k < 0联立 y = kx 和 y = k/x得 kx = k/xx² = 1 ,x = ± 1A在第二象限∴ x = - 1A( - 1,- k )AB⊥x轴,则 AB = |-k| = - kS(△ABO) = 1/2 *OB*AB = 1/2 * 1 * (-k) = 3/2∴ k = - 3