Two resistors of resistances `R_(1)=100 pm 3` ohm and `R_(2)=200 pm 4` ohm are connected (a) in series, (b) in parallel. Find the equivalent resistance of the (a) series combination, (b) parallel combination. Use for (a) the relation `R=R_(1)+R_(2)` and for (b) `1/(R')=1/R_(1)+1/R_(2)` and `(Delta R')/R'^(2)=(Delta R_(1))/R_(1)^(2)+(Delta R_(2))/R_(2)^(2)`