- #1
shen07
- 54
- 0
\(\displaystyle f:\mathbb{C}\rightarrow\mathbb{C}
\\
f(z)=\left\{\begin{array} \frac{(\bar{z})^2}/ {z} \quad z\neq0 \\
0 \quad z=0
\end{array}
\right.\)
Show that f is differentiable at z=0, but the Cauchy Riemann Equations hold at z=0.
Well i have tried to start the first part but i am stuck, could you please help me out.
WORKING:
f is diff at z=0
if \(\displaystyle \lim_{z \to 0} \frac{f(z)-f(0)}{z-0}\; exists\\
\lim_{z\to0}\frac{ \frac{(\bar{z})^2}{z}-0}{z-0}=
\lim_{z\to0}\frac{(\bar{z})^2}{z^2}
\)
Now we get indeterminate form in the limit but how can we differentiate \(\displaystyle \bar{z}\)
\\
f(z)=\left\{\begin{array} \frac{(\bar{z})^2}/ {z} \quad z\neq0 \\
0 \quad z=0
\end{array}
\right.\)
Show that f is differentiable at z=0, but the Cauchy Riemann Equations hold at z=0.
Well i have tried to start the first part but i am stuck, could you please help me out.
WORKING:
f is diff at z=0
if \(\displaystyle \lim_{z \to 0} \frac{f(z)-f(0)}{z-0}\; exists\\
\lim_{z\to0}\frac{ \frac{(\bar{z})^2}{z}-0}{z-0}=
\lim_{z\to0}\frac{(\bar{z})^2}{z^2}
\)
Now we get indeterminate form in the limit but how can we differentiate \(\displaystyle \bar{z}\)