A series of natural numbers are
grouped as 1+(2+3)+(4+5+6)+...
such that the rth group contains r
terms. Show that the sum of the
numbers in the (2r−1)th group is
r^4 −(r−1)^4 .
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 )