Difficulty: Easy
Correct Answer: (3 + 2√2)
Explanation:
Introduction / Context:Rationalizing denominators with surds is a classic skill. Using conjugates eliminates radicals in the denominator and yields a clean exact expression.
Given Data / Assumptions:
Concept / Approach:Multiply numerator and denominator by the conjugate to create a difference of squares in the denominator.
Step-by-Step Solution:
1 / (3 − 2√2) * (3 + 2√2)/(3 + 2√2) = (3 + 2√2) / (9 − (2√2)^2).(2√2)^2 = 4 * 2 = 8.Denominator = 9 − 8 = 1.Therefore, the expression simplifies to 3 + 2√2.Verification / Alternative check:Numerical check: 3 + 2√2 ≈ 3 + 2*1.414 = 5.828; 1/(3 − 2*1.414) ≈ 1/(0.172) ≈ 5.814 (difference due to rounding of √2); exact values match symbolically.
Why Other Options Are Wrong:
Common Pitfalls:Forgetting that (a − b)(a + b) = a^2 − b^2 and mis-squaring 2√2.
Final Answer:(3 + 2√2)
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