algebra: suma per diferencia

( 1/(x^{2}+(-1)·a^{2}) ) = (1/2a)·( 1/(x+(-a)) )+(-1)(1/2a)·( 1/(x+a) )


( 1/(x^{2}+a^{2}) ) = (1/2ai)·( 1/(x+(-a)i) )+(-1)(1/2ai)·( 1/(x+ai) )


(x^{2}+(-1)·a^{2}) = (x+a)(x+(-a))
(x^{2}+a^{2}) = (x+ai)(x+(-a)i)


( c/(x^{2}+(-1)·a^{2}) ) = (c/2a)·( 1/(x+(-a)) )+(-1)(c/2a)·( 1/(x+a) )


( c/(x^{2}+a^{2}) ) = (c/2ai)·( 1/(x+(-a)i) )+(-1)(c/2ai)·( 1/(x+ai) )


( (cx)/(x^{2}+(-1)·a^{2}) ) = (c/2)·( 1/(x+(-a)) )+(c/2)·( 1/(x+a) )


( (cx)/(x^{2}+a^{2}) ) = (c/2)·( 1/(x+(-a)i) )+(c/2)·( 1/(x+ai) )