The value of \(\rm 64^{\tfrac{1}{3}}\cdot 64^{\tfrac{1}{9}}\cdot 64^{\tfrac{1}{27}}\ ...\ \infty\) is:

  1. 64
  2. 6
  3. 8
  4. 7

Answer (Detailed Solution Below)

Option 3 : 8
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Detailed Solution

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Concept:

Geometric Progression (GP):

  • The series of numbers where the ratio of any two consecutive terms is the same is called a Geometric Progression.
  • A Geometric Progression of n terms with first term a and common ratio r is represented as:

    a, ar, ar2, ar3, ..., arn-2, arn-1.

  • The sum of the first n terms of a GP is: Sn = .
  • The sum  ∞ of a GP, when |r| < 1, is: S = .

Calculation:

Given: \(\rm 64^{\tfrac{1}{3}}\cdot 64^{\tfrac{1}{9}}\cdot 64^{\tfrac{1}{27}}\ ...\ \infty\)

Let us consider the infinite series  .

Here, a =  and r = .

∴ S = .

Now, let P = 

∴ P = .

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