1. Other
2. Other
3. 3 let rr1 r2 z is an element of...

# Question: 3 let rr1 r2 z is an element of...

###### Question details

3. Let R(r1, r2) = {z is an element of C (complex numbers) | r1 < |z| < r2}. By the definition, is this set an open set? COMPLEX ANALYSIS