Question

1+2+ 2^2+......+2^n=2^n+1-1is true for all natural no.n​

Answer 1

TRUE

Step-by-step explanation:

This is GP.

a1 = 1

r = 2

number of terms = n+1

=> Sn+1 = a1{1-r^(n+1)} /( 1-r)

= 1{1-2^(n+1)}/-1

= 2^(n+1) -1

Therefore the given value of sum of GP is true.

hope this helps you