An algebra problem by Mardokay Mosazghi

Algebra Level 1

Simplify this expression 2 + 2 + 1 2 + 2 + 1 2 2 2+\sqrt{2}+\frac{1}{2+\sqrt{2}}+\frac{1}{\sqrt{2}-2}


The answer is 2.

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2 solutions

Daniel Liu
Jul 12, 2014

Adding the two fractions together first: 1 2 + 2 + 1 2 2 = 2 2 2 = 2 \dfrac{1}{2+\sqrt{2}}+\dfrac{1}{\sqrt{2}-2}=\dfrac{2\sqrt{2}}{-2}=-\sqrt{2}

Thus, 2 + 2 + 1 2 + 2 + 1 2 2 = 2 + 2 2 = 2 2+\sqrt{2}+\dfrac{1}{2+\sqrt{2}}+\dfrac{1}{\sqrt{2}-2}=2+\sqrt{2}-\sqrt{2}=\boxed{2}

Hassan Raza
Aug 7, 2014

2 + 2 + 1 2 + 2 + 1 2 2 = 2 + 2 + 1 2 + 2 + 1 2 2 = 2 ( 2 + 2 ) + 1 ( 2 2 ) + 1 ( 2 + 2 ) 2 ( 2 + 2 ) ( 2 2 ) = 2 = 2 2 4 + 2 2 + 2 + 2 2 = 2 2 4 + 2 2 2 = 4 2 = 2 \qquad \sqrt { 2 } +2+\frac { 1 }{ 2+\sqrt { 2 } } +\frac { 1 }{ \sqrt { 2 } -2 } \\ =\quad \quad \sqrt { 2 } +2+\frac { 1 }{ \sqrt { 2 } +2 } +\frac { 1 }{ \sqrt { 2 } -2 } \\ =\quad \quad \frac { -2(\sqrt { 2 } +2)+1(\sqrt { 2 } -2)+1(\sqrt { 2 } +2) }{ -2 } \\ \qquad \qquad \because (\sqrt { 2 } +2)(\sqrt { 2 } -2)=-2\\ =\quad \quad \frac { -2\sqrt { 2 } -4+\sqrt { 2 } -2+\sqrt { 2 } +2 }{ -2 } \\ =\quad \quad \frac { -2\sqrt { 2 } -4+2\sqrt { 2 } }{ -2 } \quad =\quad \frac { -4 }{ -2 } \quad =\quad \boxed { 2 }

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