Q51 of 74 Page 9

Find the sum of the products of the corresponding terms of the sequence 2, 4, 8, 16, 32 and 128, 32, 8, 2, .


First sequence : 2, 4, 8, 16, 32

Second sequence : 128, 32, 8, 2, ½

New sequence after finding the products of the corresponding terms

2 × 128, 4 × 32, 8 × 8, 16 × 2, 32 ×

or 256, 128, 64, 32, 16

Now a = 256 r = = n = 5

Now Sn =

Sn =

    =

    = 512 × = 496

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