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Mathematics

Solve the following equation:

x+1x=212.x + \dfrac{1}{x} = 2\dfrac{1}{2}.

Quadratic Equations

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Answer

Given, x+1x=212x + \dfrac{1}{x} = 2\dfrac{1}{2}

x+1x=52x2+1x=522(x2+1)=5x2x2+2=5x2x25x+2=02x24xx+2=02x(x2)1(x2)=0(x2)(2x1)=0x2=0 or 2x1=0x=2 or 2x=1x=2 or x=12.\Rightarrow x + \dfrac{1}{x} = \dfrac{5}{2} \\[1em] \Rightarrow \dfrac{x^2 + 1}{x} = \dfrac{5}{2} \\[1em] \Rightarrow 2(x^2 + 1) = 5x \\[1em] \Rightarrow 2x^2 + 2 = 5x \\[1em] \Rightarrow 2x^2 - 5x + 2 = 0 \\[1em] \Rightarrow 2x^2 - 4x - x + 2 = 0 \\[1em] \Rightarrow 2x(x - 2) - 1(x - 2) = 0 \\[1em] \Rightarrow (x - 2)(2x - 1) = 0 \\[1em] \Rightarrow x - 2 = 0 \text{ or } 2x - 1 = 0 \\[1em] \Rightarrow x = 2 \text{ or } 2x = 1 \\[1em] \Rightarrow x = 2 \text{ or } x = \dfrac{1}{2}.

Hence, roots of the given equations are 2, 12\dfrac{1}{2}.

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