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Question

What is the value of the following expression:

$(1 + x)(1 + x^2)(1 + x^4)(1 + x^8)(1 - x)$

This question was previously asked in
RRB NTPC 2019 CBT 1 Question Paper (8-Mar-2021) (Shift 2)
The correct answer is
$(1 - x^{16})$

Evaluate Algebraic Expression

To find the value of the expression, we can rearrange the terms and apply the difference of squares formula repeatedly. The difference of squares formula is $a^2 - b^2 = (a - b)(a + b)$.

Step-by-Step Simplification

  1. Rearrange the given expression: $ (1 + x)(1 + x^2)(1 + x^4)(1 + x^8)(1 - x) = (1 - x)(1 + x)(1 + x^2)(1 + x^4)(1 + x^8) $
  2. Apply the difference of squares formula to the first two terms $(1 - x)(1 + x)$: $ (1 - x)(1 + x) = 1^2 - x^2 = 1 - x^2 $ The expression becomes: $ (1 - x^2)(1 + x^2)(1 + x^4)(1 + x^8) $
  3. Apply the difference of squares formula again to $(1 - x^2)(1 + x^2)$: $ (1 - x^2)(1 + x^2) = 1^2 - (x^2)^2 = 1 - x^4 $ The expression becomes: $ (1 - x^4)(1 + x^4)(1 + x^8) $
  4. Apply the difference of squares formula to $(1 - x^4)(1 + x^4)$: $ (1 - x^4)(1 + x^4) = 1^2 - (x^4)^2 = 1 - x^8 $ The expression becomes: $ (1 - x^8)(1 + x^8) $
  5. Apply the difference of squares formula one last time to $(1 - x^8)(1 + x^8)$: $ (1 - x^8)(1 + x^8) = 1^2 - (x^8)^2 = 1 - x^{16} $

Final Result

The simplified value of the expression is $(1 - x^{16})$.

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Similar Questions

  1. If $a + b + c = 10$ and $ab + bc + ca = 31$, find the value of $a^2 + b^2 + c^2$
  2. If $a + b + c = 0$, then find the value of $\frac{(a^2+b^2+c^2)^2}{a^2b^2+b^2c^2+c^2a^2}$

  3. If $x^4 + \frac{1}{x^4} = 322$, then $x^3 - \frac{1}{x^3} = ?$
  4. If $a + b + c = 17$, $abc = 168$, and $ab + bc + ca = 94$, then $a^3 + b^3 + c^3 = ?$
  5. If $a = \frac{b^2}{b - a}$, then the value of $a^3 + b^3$ is:
  6. If $ab = 10$ and $a^{2} + b^{2} = 29$, then $(a - b)^{2} = ?$
  7. If $(x + \frac{1}{x}) = 7$, then $(x - \frac{1}{x})$ is equal to:
  8. Find the value of $\frac{(74 + 47)^2 + (74 - 47)^2}{74^2 + 47^2}$
  9. If $x = 3 + \sqrt{5}$ and $y = 3 - \sqrt{5}$, then find the value of $x^2 + y^2$.
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Important Questions from Identities

  1. The coefficient of y in the expansion of (2y – 5) 3, is:

  2. If x + y = 2 and \(\frac{1}{x}+\frac{1}{y}=\frac{18}{5}\) , then the value of (x 3+ y 3) is:

  3. If x - y = 11 and \(\rm \frac{1}{x} - \frac{1}{y} = \frac{11}{24}\)  then the value of x 3 - y 3 + x 2y 2 ?

  4. If 2x 2- 8x - 1 = 0, then what is the value of \(\rm 8x^3 - \frac{1}{x^3}\) ?

  5. If \(\rm x+ \frac{1}{x} = 4,\)  then the value of  \(\rm x^5 + \frac{1}{x^5}\)  is:

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