([tex](1+0,5)(1-0,5)+( \frac{1}{ \sqrt{2}})^{2} = \frac{5}{4} \\ \\ (a+b)(a-b)=a^{2} - b^{2} \\ \\(1^{2} -0.5)^{2})+( \frac{1}{ \sqrt{2}})^{2} = \frac{5}{4} \\ \\ (1-0.25)+( \frac{ \sqrt{2} }2)^{2} = \frac{5}{4} \\ \\ 0.75+( \frac{ \sqrt{2} }2)^{2} = \frac{5}{4} \\ \\ 0.75= \frac{75}{100} = \frac{3}{4} \\ \\ \frac{3}{4}+ \frac{ (\sqrt{2}) ^{2} }{2^{2} } = \frac{5}{4} \\ \\ \frac{3}{4} + \frac{2}{4}= \frac{5}{4} \\ \\ \frac{5}{4} = \frac{5}{4} [/tex]
