MathDB
Ellipse Problem

Source: 1988 National High School Mathematics League, Exam One, Problem 2

February 25, 2020
conicsellipse

Problem Statement

If the coordinate origin is inside the ellipse k2x2+y24kx+2ky+k21=0k^2x^2+y^2-4kx+2ky+k^2-1=0, then the range value of kk is (A)k>1(B)k1(C)1<k<1(D)0<k<1\text{(A)}|k|>1\qquad\text{(B)}|k|\neq1\qquad\text{(C)}-1<k<1\qquad\text{(D)}0<|k|<1