Exercise · ZW-COMPLEX-CONTINUITY-002 · ★☆☆ Basic
For \(f(z)=\dfrac{1}{z^2+1}\), which statement is correct?
Choose one option.
Show answer
- A. It is continuous on its whole domain; it is undefined at \(\pm i\)
Explanation
The zeros of \(z^2+1\) are \(z=\pm i\), where \(f\) is undefined. At every point of its domain it is continuous, being a quotient of polynomials.
Review the concept: Complex continuity
A function \(f\) is continuous at a point \(z_0\) of its domain if \(f(z)\) tends to the value \(f(z_0)\) as \(z\) tends to \(z_0\); it is continuous if it is so at every point of its domain.
\[\lim_{z\to z_0}f(z)=f(z_0)\]
More practice problems: complex continuity
- ZW-COMPLEX-CONTINUITY-001 At which points is f(z)=(1)/(z-2) continuous?
- ZW-COMPLEX-CONTINUITY-003 Let f(z)=(z^2-4)/(z-2) for z≠ 2 and f(2)=c. Which c makes it continuous at 2?
- ZW-COMPLEX-CONTINUITY-004 The function f(z)=bar z is:
- ZW-COMPLEX-CONTINUITY-005 Let f(z)=(z^2)/(|z|) for z≠ 0 and f(0)=0. Is it continuous at 0?
- ZW-COMPLEX-CONTINUITY-006 Let f(z)=z^2 and g(w)=(1)/(w-4). At which points is g(f(z)) continuous?
- ZW-COMPLEX-CONTINUITY-007 Let f=u+iv with u=(xy)/(x^2+y^2), v=x^2 for z≠ 0 and f(0)=0. Is it continuous at 0?
- ZW-COMPLEX-CONTINUITY-008 Compute lim _z→ 1+ibig(Re(z^2)+Im(bar z)big).
- ZW-COMPLEX-CONTINUITY-009 If f is continuous on the closed disk |z|≤ 1, which claim is certain?