Giải giùm mình phương trình x(5x3 + 2) - 2(√2x+1 - 1 ) = 0
2 câu trả lời
x(5x3+2)−2(√2x+1−1)=0(∗)DK:x≥−12.(∗)⇔5x4+2x−2√2x+1+2=0⇔2x+1−2√2x+1+1+5x4=0⇔(√2x+1−1)2+5x4=0⇔{√2x+1−1=0x4=0(do{(√2x+1−1)2≥0∀x≥−12x4≥0∀x)⇔{√2x+1=1x=0⇔{2x+1=1x=0⇔{x=0x=0⇔x=0(tm).Vayptconghiemx=0.
Hiểu biết
x
(
5
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3
+
2
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−
2
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√
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=
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2
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