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{an} and {bn} are two sequences given by...

`{a_n} and {b_n}` are two sequences given by `a_n=(x)^(1//2^n) +(y)^(1//2^n) and b_(n)=(x)^(1//2^n)-(y)^(1//2^n)` for all n `in` N. The value of `a_1 a_2 a_3……..a_n` is equal to

A

`x-y`

B

`(x+y)/(b_n)`

C

`(x-y)/(b_n)`

D

`(xy)/(b_n)`

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The correct Answer is:
To solve the problem, we need to find the product \( a_1 a_2 a_3 \ldots a_n \) where the sequences \( a_n \) and \( b_n \) are defined as follows: \[ a_n = x^{1/2^n} + y^{1/2^n} \] \[ b_n = x^{1/2^n} - y^{1/2^n} \] ### Step 1: Write down the product \( a_1 a_2 a_3 \ldots a_n \) We start by calculating the product of the first \( n \) terms of the sequence \( a_n \): \[ P = a_1 a_2 a_3 \ldots a_n = (x^{1/2} + y^{1/2})(x^{1/4} + y^{1/4})(x^{1/8} + y^{1/8}) \ldots (x^{1/2^n} + y^{1/2^n}) \] ### Step 2: Express \( P \) in terms of \( b_n \) Next, we can relate this product to the sequence \( b_n \). We know that: \[ a_n = (x^{1/2^n} + y^{1/2^n}) \quad \text{and} \quad b_n = (x^{1/2^n} - y^{1/2^n}) \] We can use the identity \( (a + b)(a - b) = a^2 - b^2 \) to express the product: \[ P \cdot b_1 b_2 b_3 \ldots b_n = (x^{1/2} + y^{1/2})(x^{1/2} - y^{1/2})(x^{1/4} + y^{1/4})(x^{1/4} - y^{1/4}) \ldots (x^{1/2^n} + y^{1/2^n})(x^{1/2^n} - y^{1/2^n}) \] ### Step 3: Simplify the expression Using the above identity, we can simplify the product: \[ P \cdot b_1 b_2 b_3 \ldots b_n = (x^{1/2})^2 - (y^{1/2})^2 + (x^{1/4})^2 - (y^{1/4})^2 + \ldots + (x^{1/2^n})^2 - (y^{1/2^n})^2 \] This results in: \[ = x^{1} - y^{1} = x - y \] ### Step 4: Find the product of \( b_n \) Next, we need to compute \( b_1 b_2 b_3 \ldots b_n \): \[ b_n = x^{1/2^n} - y^{1/2^n} \] Thus, the product \( b_1 b_2 b_3 \ldots b_n \) can be calculated as: \[ b_1 b_2 b_3 \ldots b_n = (x^{1/2} - y^{1/2})(x^{1/4} - y^{1/4})(x^{1/8} - y^{1/8}) \ldots (x^{1/2^n} - y^{1/2^n}) \] ### Step 5: Combine results Now we can express \( P \): \[ P = \frac{x - y}{b_1 b_2 b_3 \ldots b_n} \] ### Final Result Thus, the value of \( a_1 a_2 a_3 \ldots a_n \) is given by: \[ a_1 a_2 a_3 \ldots a_n = \frac{x - y}{b_1 b_2 b_3 \ldots b_n} \]
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