1.下列函数有些什么奇点?如果是极点,指出它的级数:-|||-(1) dfrac (1)(z{({z)^2+1)}^2} ;-|||-(2) dfrac (sin z)({z)^3} =-|||-(3) dfrac (1)({z)^3-(z)^2-z+1} ;-|||-(4) dfrac (ln (z+1))(z) ;-|||-(5) dfrac (z)((1+{z)^2)(1+(e)^pi z)} ;-|||-(6) dfrac (1)({e)^2-1} ;-|||-(7) dfrac (1)({z)^2((e)^z-1)}-|||-(8) dfrac ({z)^2n}(1+{z)^n} (n为正整数);-|||-(9) dfrac (1)(sin {2)^2} .