Chapter 21.8, Problem 37E

(a)

To determine

The curve represented by the equation $x^2+k{y}^2=a^2$ when $k=1$.

(b)

To determine

The curve represented by the equation $x^2+k{y}^2=a^2$ when $k<0$.

(c)

To determine

The curve represented by the equation $x^2+k{y}^2=a^2$ when $k>0\left(k\ne 1\right)$.