cho x+y và x^2+y^2 =a^2 . Tính Q =x^2020 +y^2020 21/11/2021 Bởi Hailey cho x+y và x^2+y^2 =a^2 . Tính Q =x^2020 +y^2020
`x+y=a` `⇒x^2+y^2+2xy=a^2` `⇒2xy=0` \(⇒\left[ \begin{array}{l}x=0\\y=0\end{array} \right.\) \(⇒\left[ \begin{array}{l}y=a\\x=a\end{array} \right.\) \(⇒\left[ \begin{array}{l}Q=0+a^{2020}=a^{2020}\\Q=a^{2020}+0=a^{2020}\end{array} \right.\) Vậy `Q=a^{2020}` Bình luận
`x+y=a`
`⇒x^2+y^2+2xy=a^2`
`⇒2xy=0`
\(⇒\left[ \begin{array}{l}x=0\\y=0\end{array} \right.\)
\(⇒\left[ \begin{array}{l}y=a\\x=a\end{array} \right.\)
\(⇒\left[ \begin{array}{l}Q=0+a^{2020}=a^{2020}\\Q=a^{2020}+0=a^{2020}\end{array} \right.\)
Vậy `Q=a^{2020}`