(-2*a*b*1i)/((a^2+b^2)*((a-b*1i)-1/(a-b*1i))) = -((a+1i*b)+(a-1i*b))*((a+1i*b)-(a-1i*b))/(2*((a+1i*b)*(a-1i*b))*((a-1i*b)-1/(a-1i*b)))