How can I solve complex number equation ?
How do you simplify -LSB- math -RSB- 1 / -LRB- 1-i -RRB- -1 / -LRB- 1-2i -RRB- +1 / -LRB- 1-3i -RRB- -1 / -LRB- 1-4i -RRB- +1 / -LRB- 1-5i -RRB- -1 / -LRB- 1-6i -RRB- + ... 1 / -LRB- 1-19i -RRB- -1 / -LRB- 1 +20 i -RRB- -LSB- / math -RSB- ?