Question

If I +2 +2
+2^2+2^3 + + n terms is 1025, then the value of n is
a) 11
b)12
c) 10
d) 13​

Answer 1

Answer:

option b.............

Answer 2

Lets compare first two terms,

2:1 = 2

then 2nd and third,

4:2=2

You'll notice that this ratio remains constant.

Therefore,

the terms are in GP aka geometric progression.

Now for sum till n terms in a GP is given by,

where a is the sum and r is common ratio and n is the no. of terms,

Equating these two after subsituting the values,

Therefore we have n as 10.

$\huge❥ᴛʜᴀ᭄ɴᴋs </p><p></p><p>$