Verification For each differential equation, verify by $$differen$-$

tiation and substitution that the given function is $$a solution.

y$\text{'}=$y$2+4(|$t$|<$$4)$;$,$y$=2$tan$2$t

y$\text{'}=1$ty$+$t$($t$>0)$;$,$y$=3$t$+$t$2$

y$\text{'}=2$yt$+$t$($t$>0)$;$,$y$=$t$2$lnt

y$\text{'}-4$ty$=1$;

y$=0$te$-2($s$2-$t$2)$ds