Author: Tinku Tara

Question Number 217857 by hardmath last updated on 22/Mar/25 $$\mathrm{Prove}\:\mathrm{that}: \\ $$$$\sqrt[{\mathrm{3}}]{\mathrm{cos20}°}\:+\:\sqrt[{\mathrm{3}}]{\mathrm{cos80}°}\:+\:\sqrt[{\mathrm{3}}]{\mathrm{cos160}°}\:=\:\sqrt[{\mathrm{3}}]{\frac{\mathrm{3}\:\centerdot\:\sqrt[{\mathrm{3}}]{\mathrm{9}}\:−\:\mathrm{6}}{\mathrm{2}}} \\ $$ Answered by Frix last updated on 22/Mar/25 $$\mathrm{Staying}\:\mathrm{in}\:\mathbb{R}\:\Rightarrow\:\sqrt[{\mathrm{3}}]{\mathrm{cos}\:\mathrm{20}°}=−\sqrt[{\mathrm{3}}]{\mathrm{cos}\:\mathrm{160}°}\:\Rightarrow \\ $$$$\mathrm{cos}\:\mathrm{80}°\:=\frac{\mathrm{3}}{\mathrm{2}}\sqrt[{\mathrm{3}}]{\mathrm{9}}−\mathrm{3}\approx.\mathrm{12} \\…

Question Number 217822 by Ari last updated on 21/Mar/25 Answered by mr W last updated on 22/Mar/25 $$\left.{a}\right) \\ $$$$\mathrm{0}.\mathrm{10}×\mathrm{0}.\mathrm{05}=\mathrm{0}.\mathrm{5\%} \\ $$$$\left.{b}\right) \\ $$$${can}\:{not}\:{be}\:{determined},\:{but}\:{at}\:{least} \\…