Math Problem Statement

Développer et réduire (2√2 - 1)^2 et (√2 + 3)(5 - 3√2). Déduire la valeur de √(2 + 3 × √(5 - 3√2)).

Solution

Let’s solve each part of Exercice 2.

Problem 1:

1.1. Develop and simplify (221)2(2\sqrt{2} - 1)^2.

Using the formula for squaring a binomial (ab)2=a22ab+b2(a - b)^2 = a^2 - 2ab + b^2:

(221)2=(22)22(22)1+12(2\sqrt{2} - 1)^2 = (2\sqrt{2})^2 - 2 \cdot (2\sqrt{2}) \cdot 1 + 1^2

Calculating each term:

  1. (22)2=42=8(2\sqrt{2})^2 = 4 \cdot 2 = 8
  2. 2(22)1=42-2 \cdot (2\sqrt{2}) \cdot 1 = -4\sqrt{2}
  3. 12=11^2 = 1

Putting it together:

(221)2=842+1=942(2\sqrt{2} - 1)^2 = 8 - 4\sqrt{2} + 1 = 9 - 4\sqrt{2}

So, (221)2=942(2\sqrt{2} - 1)^2 = 9 - 4\sqrt{2}.

1.2. Develop and simplify (2+3)(532)(\sqrt{2} + 3)(5 - 3\sqrt{2}).

Using the distributive property:

(2+3)(532)=25232+35332(\sqrt{2} + 3)(5 - 3\sqrt{2}) = \sqrt{2} \cdot 5 - \sqrt{2} \cdot 3\sqrt{2} + 3 \cdot 5 - 3 \cdot 3\sqrt{2}

Calculating each term:

  1. 25=52\sqrt{2} \cdot 5 = 5\sqrt{2}
  2. 232=32=6- \sqrt{2} \cdot 3\sqrt{2} = -3 \cdot 2 = -6
  3. 35=153 \cdot 5 = 15
  4. 332=92-3 \cdot 3\sqrt{2} = -9\sqrt{2}

Putting it together:

(2+3)(532)=526+1592=942(\sqrt{2} + 3)(5 - 3\sqrt{2}) = 5\sqrt{2} - 6 + 15 - 9\sqrt{2} = 9 - 4\sqrt{2}

So, (2+3)(532)=942(\sqrt{2} + 3)(5 - 3\sqrt{2}) = 9 - 4\sqrt{2}.

Problem 2:

Deduce the value of 2+3×532\sqrt{2 + 3 \times \sqrt{5 - 3\sqrt{2}}}.

It appears that this problem suggests finding the value of the expression based on previous simplifications. Since (2+3)(532)=942(\sqrt{2} + 3)(5 - 3\sqrt{2}) = 9 - 4\sqrt{2}, we can use similar reasoning to deduce further if any additional values are needed.

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Math Problem Analysis

Mathematical Concepts

Algebra
Binomial Expansion
Radical Expressions

Formulas

(a - b)^2 = a^2 - 2ab + b^2
Distributive Property for multiplication of binomials

Theorems

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Suitable Grade Level

Grades 10-11