2 câu trả lời
$\sqrt[]{3+2\sqrt[]{2}} - \sqrt[]{3-2\sqrt[]{2}}$
$ = \sqrt[]{( \sqrt[]{2} )^2 + 2 . \sqrt[]{2} . 1 + 1^2} - \sqrt[]{( \sqrt[]{2} )^2 - 2 . \sqrt[]{2} . 1 + 1^2}$
$ = \sqrt[]{( \sqrt[]{2} + 1 )^2} - \sqrt[]{( \sqrt[]{2} - 1 )^2} $
$ = | \sqrt[]{2} + 1 | - | \sqrt[]{2} - 1 | $
$ = \sqrt[]{2} + 1 - ( \sqrt[]{2} - 1 )$
$ = \sqrt[]{2} + 1 - \sqrt[]{2} + 1 $
$ = 2 $
`\sqrt{3+2\sqrt{2}}- \sqrt{3-2\sqrt{2}}`
`=` `\sqrt{1+2\sqrt{2} +2` `-` `\sqrt{1-2\sqrt{2}+2`
`=` `\sqrt{(1+\sqrt{2})^{2}` `-` `\sqrt{(1-\sqrt{2})^{2}`
`=` `|1+\sqrt{2}|` `-` `|1-\sqrt{2}|`
`=` `1+\sqrt{2} -(\sqrt{2}-1)`
`=` `1+\sqrt{2}-\sqrt{2}+1`
`=` `2`
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