Question

write all formulas of arithmetic progressions

Class 10th Cbse board

Answer 1

1)sum of n terms....an=a+(n-1)d
2)last term......an=n/2(a+l)
3)sum of n positive intigers.....n(n+1)/2
4)sum of first n terms.....sn=n/2(2a+(n-1)d
....hope it helps u...

Answer 2

Last or the required term , an = a+(n-1)d , where a is the first term , d is the common difference.

Sum of the 1st n terms , Sn=n/2(a+an) = n/2 (a+(n-1)d

Common difference , d = a2-a1