Challenging +1.8 This question requires students to recognize that Rehman's identity is false, set up the equation where both sides happen to equal each other, and solve a non-trivial equation involving logarithms. It demands algebraic manipulation beyond routine log laws and the insight to find when a false identity accidentally holds true—a problem-solving task requiring multiple steps and conceptual understanding rather than standard textbook application.
5. While working on a logarithms problem on one of the whiteboards in the Maths corridor, Rehman confidently asserts the following:
"For all positive real numbers \(x\) and \(y\), we know that \(\log _ { 2 } x - \log _ { 2 } y \equiv \frac { \log _ { 2 } x } { \log _ { 2 } y }\)."
Soufiane, who happens to be passing, knows that this is wrong. He attempts to prove this by counterexample, picking two values of \(x\) and \(y\) off the top of his head and plugging both sides of the false identity into his calculator. To his dismay, both sides give exactly the same answer, and Rehman smugly walks off uncorrected.
What is the range of possible values of \(x\) that Soufiane picked? [0pt]
[6] [0pt]
5. While working on a logarithms problem on one of the whiteboards in the Maths corridor, Rehman confidently asserts the following:\\
"For all positive real numbers $x$ and $y$, we know that $\log _ { 2 } x - \log _ { 2 } y \equiv \frac { \log _ { 2 } x } { \log _ { 2 } y }$."\\
Soufiane, who happens to be passing, knows that this is wrong. He attempts to prove this by counterexample, picking two values of $x$ and $y$ off the top of his head and plugging both sides of the false identity into his calculator. To his dismay, both sides give exactly the same answer, and Rehman smugly walks off uncorrected.
What is the range of possible values of $x$ that Soufiane picked?\\[0pt]
[6]\\[0pt]
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\hfill \mbox{\textit{SPS SPS FM 2024 Q5 [6]}}