观察下列一组分式：-b/a,b²/2a,-b³/3a,b四次方/4a,-b五次方/5a,则第（n+1）个分式为_________

观察下列一组分式：-b/a,b²/2a,-b³/3a,b四次方/4a,-b五次方/5a,则第（n+1）个分式为_________
观察下列一组分式：-b/a,b²/2a,-b³/3a,b四次方/4a,-b五次方/5a,则第（n+1）个分式为_________

观察下列一组分式：-b/a,b²/2a,-b³/3a,b四次方/4a,-b五次方/5a,则第（n+1）个分式为_________
观察下列一组分式：-b/a,b²/2a,-b³/3a,b四次方/4a,-b五次方/5a,则第（n+1）个分式为(-1)^(n+1)b^(n+1)/(n+1)a

(-b)^(n+1)/(n+1)a

(-b)^n/(na)