## Thomas' Calculus 13th Edition

a. Domain : A set of all points $(x,y)$ lies when $x^2+y^2 =1$ b. Range: Real numbers c. The level curves are the circles whose center is at (0,0) with radius $r \gt 1$ d. Boundary point lies at the circle $x^2+y^2=1$ e. Open f. Unbounded