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Question
Simplify the following:
`sqrt(3 - 2sqrt(2))`
Simplify
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Solution
Given: `sqrt(3 - 2sqrt(2))`
Stepwise calculation:
1. Assume the expression inside the square root can be written as a square of a binomial involving square roots: `3 - 2sqrt(2) = (sqrt(a) - sqrt(b))^2 = a + b - 2sqrt(ab)` where (a) and (b) are positive numbers.
2. Equate terms: a + b = 3
`2sqrt(ab) = 2sqrt(2)`
⇒ `sqrt(ab) = sqrt(2)`
Squaring: ab = 2
3. Solve the system: a + b = 3
ab = 2
4. The pair (a, b) that satisfies both is a = 1, b = 2 because:
1 + 2 = 3
1 × 2 = 2
5. So, `3 - 2sqrt(2) = (sqrt(2) - 1)^2`
6. Taking the square root: `sqrt(3 - 2sqrt(2))`
= `sqrt((sqrt(2) - 1)^2`
= `|\sqrt(2) - 1|`
Since `sqrt(2) ≈ 1.414, sqrt(2) - 1 > 0`,
Thus, `sqrt(3 - 2sqrt(2)) = sqrt(2) - 1`.
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Chapter 1: Rational and Irrational Numbers - Exercise 1D [Page 28]
