Question

Find S10 of the series 3+5+7+9+........

Answer 1

Answer:

heya mate there's your answer

Given series 3+5+7+9...............is in AP.

let first term of the AP be a1 =3

second term of the AP be a2=5

and common difference of the AP be d

d=a2-a1

d=5-3

d=2

So common difference of the AP is d=2

we know that,sum of n terms in an AP is,

Sn=n/2[2a1+(n-1)d]

so sum of 10 terms of an AP is,

S10=10/2[2×3+(10-1)2]

=5[6+9×2]

=5[6+18]

=5(24)

=120

So sum of 10 terms of an AP is 120.

hope it helps you

Thank you