2+22+23+24+25+26+27+28+29+210+211 =___
To find:
2+22+23+24+25+26+27+28+29+210+211
Here,
t2t1=222=2
t3t2=2322=2
and clearly
t2t1=t3t2=t4t3=....
So, the given series is in Geometric progression.
Now, in 2+22+23+24+25+26+27+28+29+210+211
First term (a)=2
Common ration (r)=t2t1=222=2
Number of terms (n)=11
Since, Sum of the first n-terms in G.P is,
Sn=a(rn−1)r−1,r>1
⇒S12=2(211−1)2−1
⇒S12=2.211−2
⇒S12=212−2
Hence, Option B is correct.