# Sum of Complex Numbers

Algebra Level 3

Let $$f(A,B)=\frac{A+Bi}{A-Bi}$$, where $$A$$ and $$B$$ are non-zero real numbers. If $$C$$ and $$D$$ are real numbers such that $f(2,1)+f(4,2)+f(6,3)+f(8,4)+f(10,5)=C+Di,$ what is the value of $$C + D?$$

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