$1.(20$ pts$.)$ In the following, use the iteration method to find the asymptotic notation of the order of growth of the recurrences:

#

$1$ if n $1($a$)$ Tpnq $2$Tpn$\{2$q $`$ b if n $1.$ #

c if n $0($b$)$ Tpnq $$ Tpn $1$q $`$ n $`$ b if n $1.$