Question

1/2

, 2/3,3/4,


…then nth term of this AP is:

a) /n+1


b) /2n+1


c) /2n


d) 2−1/2n+1​

Answer 1

Step-by-step explanation:

Correct option is C)/2n

=(2n−1)

⇒ a

1

=2×1−1=1

⇒ a

2

=2×2−1

=4−1

=3

⇒ d=a

1

−a

1

=3−1

∴ d=2

⇒ S

1

=

2

n

[2a

1

+(n−1)d]

=

2

n

[2(1)+(n−1)2]

=

2

n

[2+2n−2]

=

2

n

×2n

=n

2