T 7 a b O LLL Find the radius of convergence of the power series for the following functions expanded about the indicated point 2 1 about z 3 i about z 0 COS Z 22 4 c d sin sin about 2 i z about 2 i Solution a Removable singularity at z 1 poles at i 1 R 3 to i nearest singularity b singularities at 7 2 are removable c removable at z 0 poles at 2 R ni 2 TV d 2 sin z simple poles at z 0 R T