What is the absolute value of \( 2-i \) ? A. 2 B. \( \sqrt{3} \) C. \( \sqrt{5} \) D. \( 2+i \) E. \( -2+i \)

Using the change of base formula, express \( \log_{2}(8) \) in terms of common logarithm.

7. Исследуйте но чётность и нечетность функции а) \( \mathrm{y}=4 \mathrm{x}-2 \mathrm{x}^{3}+6 \mathrm{x}^{5} \quad \); б) \( f(x)=\frac{5}{x^{4}+4 x^{2}} \)

b) \( \left(\frac{6}{4} \sqrt{48}+\sqrt{75}-\frac{1}{2} \sqrt{12}\right)+\frac{2}{\sqrt{3}}+\frac{4}{\sqrt{27}} \)

20. Vereinfache im Kopf. \( \begin{array}{lll}\text { a) }\left(5^{\frac{4}{5}}\right)^{\frac{5}{2}} & \text { b) }\left(36^{\frac{3}{4}}\right)^{\frac{2}{3}} & \text { c) }\left(49^{-\frac{6}{7}}\right)^{\frac{7}{12}}\end{array} \)

What is the absolute value of \( 2-i \) ? A. 2 B. \( \sqrt{3} \) C. \( \sqrt{5} \) D. \( 2+i \) E. \( -2+i \)