In the case of *a=1 , b=1 , *and* k=1,
*the graph of the equation is as following;

Let's try to change *a* for various number,
with the b and k (b=1,k=1) are fixed!

*a=2*

*a=3*

*a=4*

If the number of a is bigger number, the graph is expand and the shape is similar to circle having radius of a graduary.

Let's try to change *b* for various number,with
*a *and*k *are fixed (*a*=1,*k*=1)!

*b=2*

*b=3*

*b=4*

As changing the number of *b* begger,
expanding inside ring.

Let's try to change
the number of *k* for various number,with *a=1 , b=1 *!

*k=2*

* k=3*

* k=4*

* k=5 *

* *It seems that
the number of k and the the number of k are same number.