Question

双曲线x²+ky²=1的离心率是2,问k的值

Answer 1

x²+ky²=1等价于x²+y²/(1/k)=1

所以a^2=1,b^2=1/k,c^2=k+1/k

所以e^2=c^2/a^2=4 解得

k=1/3