Tìm GTNN,GTLN của \(y=3\sqrt{x-1}+4\sqrt{5-x}\)

Tính C = \(x^3+3x+2015\) với \(x=\sqrt[3]{2+\sqrt{5}}+\sqrt[3]{2-\sqrt{5}}\)

Tính B = x + y biết :

\(\left(x+\sqrt{x^2+2019}\right)\left(y+\sqrt{y^2+2019}\right)=2019\)

\(\left(1-\frac{1}{21}\right).\left(1-\frac{1}{28}\right).\left(1-\frac{1}{36}\right)...\left(1-\frac{1}{1326}\right)\)

\(=\frac{20}{21}.\frac{27}{28}.\frac{35}{36}...\frac{1325}{1326}\)

\(=\frac{40}{42}.\frac{54}{56}.\frac{70}{72}...\frac{2650}{2652}\)

\(=\frac{5.8}{6.7}.\frac{6.9}{7.8}.\frac{7.10}{8.9}...\frac{50.53}{51.52}\)

\(=\frac{5.6.7...50}{7.8.9...52}.\frac{8.9.10...53}{6.7.8...51}\)

\(=\frac{5.6}{51.52}.\frac{52.53}{6.7}\)

\(=\frac{5.52}{51.7}=\frac{260}{357}\)

Ủng hộ mk nha ^_-