Question

For the AP 1, 15,29 ... prove that a10=S10-S9​

Answer 1

Step-by-step explanation:

a1=1 a2=15 a3=29

D=15-1=14

a10 =$10-$9

=n/2(2a+(n-1)d) -- n/2(2a+(n-1)d)

=10/2(2*1+(10-1)14) - 9/2(2*1+(9-1)14)

=5(2+(9)14)-9/2(2+(8)14)

=5(2+126)-9/2(2+112)

=5(128)-9/2(114)

=640-513

=127

a10=127