Φ(z)=log(z−1)+log(z+1)=log((z−1)(z+1))=log(z2−1). Now, as z approaches the y-axis from one side or the other, the argument of log(z2−1) a...Φ(z)=log(z−1)+log(z+1)=log((z−1)(z+1))=log(z2−1). Now, as z approaches the y-axis from one side or the other, the argument of log(z2−1) approaches either π or −π. Farther away from the origin the flow stops being radial and is pushed to the right by the uniform flow. It is the point on the x-axis where the flow from the source exactly balances that from the uniform flow.
