Ta có: \(\left(2a^3-\dfrac{1}{50}a+\dfrac{2}{5}a^5\right)\left(\dfrac{1}{2}a^6-\dfrac{1}{10}a^2+\dfrac{3}{100}a^4\right)\)
\(=a^9-\dfrac{1}{5}a^5+\dfrac{3}{50}a^7-\dfrac{1}{100}a^7+\dfrac{1}{500}a^3-\dfrac{3}{5000}a^5+\dfrac{1}{5}a^{11}-\dfrac{1}{25}a^7+\dfrac{3}{250}a^9\)
\(=\dfrac{1}{5}a^{11}+\dfrac{253}{250}a^9+\dfrac{1}{100}a^7-\dfrac{1003}{5000}a^5+\dfrac{1}{500}a^3\)