If nth term of an ap is 2n+1 find the sum of first n terms of ap
Answers
Answered by
2
Step-by-step explanation:
aN=2n+1
taking n=1,2
a1=2×1+1
=2+1=3
a2=2×2+1
=4+1=5
d=a2-a1
=5-3=2
Sn=n/2[2a+(n-1)d]
=n/2[2×3+(n-1)2]
=n/2[6+2n-2]
=n/2[4+2n]
=2n+n sq.
Similar questions