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Compute the limit of the given function

Evaluate the limit.

    \[ \lim_{x \to +\infty} \left( x^2 - \sqrt{x^4 -x^2 + 1} \right). \]


First, we multiply and divide by the conjugate of the expression, then simplify and take the limit,

    \begin{align*}  \lim_{x \to +\infty}\left( x^2 - \sqrt{x^4 - x^2 + 1} \right) &= \lim_{x \to +\infty} \left( \frac{\left(x^2 - \sqrt{x^4-x^2+1} \right)\left(x^2 + \sqrt{x^4-x^2+1} \right)}{x^2 + \sqrt{x^4-x^2+1}} \right)\\[9pt]  &= \lim_{x \to +\infty} \frac{x^4 - x^4 + x^2 - 1}{x^2 + \sqrt{x^4 - x^2 + 1}} \\[9pt]   &= \lim_{x \to +\infty} \frac{x^2-1}{x^2 + x^2 \sqrt{1 - \frac{1}{x^2} + \frac{1}{x^4}}} \\[9pt]  &= \lim_{x \to +\infty} \frac{1 - \frac{1}{x^2}}{1 + \sqrt{1-\frac{1}{x^2} + \frac{1}{x^4}}} \\[9pt]  &= \frac{1}{2}. \end{align*}

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