Basic Mathematics & Logarithm
Logarithm Properties
Grade 11

Question:

<p>Let \(x = (\text{antilog}_2 3) \cdot \log_3 2\), \(y = \log_2(\log_3(\log_2 512))\) and \(z = \log_5 3 \cdot \log_7 5 \cdot \log_2 7\), then \(xyz\) is equal to:</p>

Step-by-Step Solution

Key Concept: Recognize that antilog_a(b) = a^b, use the change of base formula identity log_a(b) · log_b(a) = 1, and apply the chain rule log_a(b) · log_b(c) · log_c(d) = log_a(d) for logarithmic products.
<p><strong>Step 1: Calculate x</strong></p><p>x = (antilog₂ 3) · log₃ 2 = 2³ · log₃ 2 = 8 · log₃ 2</p><p>Using the identity log_a(b) · log_b(a) = 1:</p><p>log₃ 2 · log₂ 3 = 1, so log₃ 2 = 1/log₂ 3</p><p>Therefore: x = 8 · (1/log₂ 3) = 8/log₂ 3</p><p><strong>Step 2: Calculate y</strong></p><p>First: log₂ 512 = log₂ 2⁹ = 9</p><p>Then: log₃(log₂ 512) = log₃ 9 = log₃ 3² = 2</p><p>Therefore: y = log₂(log₃(log₂ 512)) = log₂ 2 = 1</p><p><strong>Step 3: Calculate z</strong></p><p>z = log₅ 3 · log₇ 5 · log₂ 7</p><p>Using the chain rule: log_a(b) · log_b(c) · log_c(d) = log_a(d)</p><p>Reorder: z = log₅ 3 · log₅ 7 · log₇ 2... Actually, apply directly:</p><p>z = log₂ 3 (using the property that log₅ 3 · log₇ 5 · log₂ 7 = log₂ 3 via change of base)</p><p><strong>Step 4: Calculate xyz</strong></p><p>xyz = (8/log₂ 3) · 1 · log₂ 3 = 8</p><p>∴ Answer: <strong>8</strong></p>
Correct Answer: 8

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