Toán Lớp 9: Nhanh giúp mk vs mk đang gấp ai đầu vote 5 sao
a,chứng minh. 11+6√2=(3+√2)^2
b,chứng minh. √11+6√2+√11-6√2=6
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Toán Lớp 9: Nhanh giúp mk vs mk đang gấp ai đầu vote 5 sao
a,chứng minh. 11+6√2=(3+√2)^2
b,chứng minh. √11+6√2+√11-6√2=6
Comments ( 2 )
$=11+2.3.\sqrt{2}$
$=9+2.3.\sqrt{2}+2$
$=(3+\sqrt{2})^2(đpcm)$
b,
$=\sqrt{11+2.3.\sqrt{2}}+\sqrt{11-2.3.\sqrt{2}}$
$=\sqrt{9+2.3.\sqrt{2}+2}+\sqrt{9-2.3.\sqrt{2}+2}$
$=\sqrt{(3+\sqrt{2})^2}+\sqrt{(3-\sqrt{2})^2}$
$=|3+\sqrt{2}|+|3-\sqrt{2}|$
$=3+\sqrt{2}+3-\sqrt{2}$
$=6(đpcm)$