As the number of possible tests for even simple software components is practically infinite, all software testing uses some strategy to select tests 

1. Although testing can determine the correctness of software under the assumption of some specific hypothese

• conditions but can only establish that it does not function properly under specific conditions. 

(a+b)² = a² + b² +2ab,,,,,,,,,H₂SO₄

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\(x = {-b \pm \sqrt{b^2-4ac} \over 2a}\)

\(\cos (2\theta) = \cos^2 \theta - \sin^2 \theta\)

\(\lim_{x \to \infty} \exp(-x) = 0\)

\(k_{n+1} = n^2 + k_n^2 - k_{n-1}\)

f(n) = n^5 + 4n^2 + 2 |_{n=17}
 

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