Ta có:
` a^{2020} ≥ 0 ; b^{2020} ≥ 0 ; c^{2020} ≥ 0 `
` => a^{2020} + b^{2020} + c^{2020} ≥ 0 `
Do: ` a + b + c = 3 ; a , b , c > 0 `
` => a^{2020} + b^{2020} + c^{2020} ≥ 3 `
Vậy ` M i n_{a^{2020} + b^{2020} + c^{2020}} ` là ` 3, ` Dấu ` "=" ` xảy ra khi: ` a = b = c = 1 `