Airthmetic progression Example

Show that 1,2,3,4..........n are in A.P

a1=1

a2=2

d1=2-1

     =1

d2=3-2=1

d1=d2

Hence proved this sequence are in A.P

  Show that 2,4,6..........n are in A.P

a1=2

a2=4

d1=4-2

     =2

d2=6-4=2

d1=d2

Hence proved this sequence are in A.P