双曲线2X^2-Y^2=K 焦距是6,则K等于多少
问题描述：
双曲线2X^2-Y^2=K 焦距是6,则K等于多少
到底是正负6 还是6 一个值还是两个值呀 晕
答
2X^2-Y^2=KX^2/(K/2) - Y^2/K = 1a^2 = |K|/2b^2 = |K|c^2 = a^2 + b^2 = 3|K|/22c = 6c^2 = 3*3 = 99 = 3|K|/2|K| = 6k = ±6当然是两个值啊.就是有2个解.k=6 时,是向 x 正方向和负方向开口,焦点在x轴上.k = -6 ,焦...