The Total solution for NCERT class 6-12
Find the sum of the products of the corresponding terms of the sequences2, 4, 8, 16, 32 and 128, 32, 8, 2, 1/2.
The required sum= 2 x 128 + 4 x 32 + 8 x 8 + 16 x 2 + 32 x ½
= 64[4 + 2 + 1 + ½ +1/22]
Now, it’s seen that
4, 2, 1, ½, 1/22 isa G.P.
With first term, a =4
Common ratio, r =1/2
We know,
Therefore, therequired sum = 64(31/4) = (16)(31) = 496