In △ADB and △EDC
AD=DE and BD=DC since AD is a median of △ABC
∠ADB=∠EDC(vertically opposite angles)
∴△ADB≅△EDC by SAS axiom
∴AB=EC .......(1) by CPCT
In △AEC,
AC+EC>AE
∵ The sum of any two sides of a triangle is greater than the third side.
⇒AC+AB>AE from (1)
⇒AB+AC>AE
⇒AB+AC>2AD