Question:

If aa and b b are positive integers such that a2b2a^2 - b^2 is a prime number, then a2b2a^2 - b^2 is

Updated On: May 11, 2024
  • a+ba+b
  • aba - b
  • abab
  • 1
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The Correct Option is A

Solution and Explanation

aa and b b are positive integers and a2b2a^2 - b^2 is a prime number.
Since, a2b2=(a+b)(ab)a^2 - b^2 = (a+ b) (a - b) product of two numbers.
\therefore Either a+b=1a + b = 1 or ab=1a - b = 1
Case I : a+b=1a + b = 1 \Rightarrow Either a=0a = 0 or b=0b = 0 then a2b2=1a^2 - b^2 = 1 or 1-1
which is not a prime number.
\therefore This case is not possible
Case II : ab=1aa - b = 1 \rightarrow a and bb can be taken anything with b<ab < a.
ln this case a2b2=a+ba^2 - b^2 = a + b is a prime number.
   a2b2=a+b.\therefore \:\:\: a^2 - b^2 = a + b.
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Concepts Used:

Binomial Theorem

The binomial theorem formula is used in the expansion of any power of a binomial in the form of a series. The binomial theorem formula is 

Properties of Binomial Theorem

  • The number of coefficients in the binomial expansion of (x + y)n is equal to (n + 1).
  • There are (n+1) terms in the expansion of (x+y)n.
  • The first and the last terms are xn and yn respectively.
  • From the beginning of the expansion, the powers of x, decrease from n up to 0, and the powers of a, increase from 0 up to n.
  • The binomial coefficients in the expansion are arranged in an array, which is called Pascal's triangle. This pattern developed is summed up by the binomial theorem formula.