Question Number 148639 by tabata last updated on 29/Jul/21

find singular point of this following and  whats the type of singular point ?    (1)f(z)=(1/(lnz))    (2)f(z)=((1−cos(z+i))/(z(z^2 +1)^2 ))    (3)f(z)=((sinz)/(z^2 +z))    (4)f(z)=((sin2z)/z^2 )

Answered by mathmax by abdo last updated on 30/Jul/21

1) f(z)=(1/(lnz))   o is singular point  2)f(z)=((1−cos(z+i))/(z(z−i)^2 (z+i)^2 ))   les points singuliers sont les poles  o ,+^− i  3)f(z)=((sinz)/(z(z+1))) ⇒les point singuliers sont o et −1  4)f(z)=((sin(2z))/z^2 ) ⇒o est point singulier (pole dordre 2)

Commented bySozan last updated on 30/Jul/21

thank you sir can you give me the series   ajust number (1) please