Đáp án: Giải thích các bước giải: $x = 10x³ – x$ $10x³ – x – x = 0$ $10x³ – 2x = 0$ $2x. ( 5x² – 1) = 0$ \(\left[ \begin{array}{l}2x = 0 \\5x² – 1 = 0\end{array} \right.\) \(\left[ \begin{array}{l}x=0\\5x² = 1\end{array} \right.\) \(\left[ \begin{array}{l}x=0\\x²=\dfrac{1}{5}\end{array} \right.\) \(\left[ \begin{array}{l}x=2\\x=±\dfrac{√5}{5}\end{array} \right.\) Bình luận
$10x^3-x=x$ $\Leftrightarrow 10x^3-2x=0$ $\Leftrightarrow 2x(5x^2-1)=0$ – TH1: $2x=0\Leftrightarrow x=0$ – TH2: $5x^2-1=0$ $\Leftrightarrow 5x^2=1$ $\Leftrightarrow x^2=\frac{1}{5}$ $\Leftrightarrow x=\pm \frac{1}{\sqrt5}$ Vậy $S= \{ 0; \pm \frac{1}{\sqrt5}\}$ Bình luận
Đáp án:
Giải thích các bước giải:
$x = 10x³ – x$
$10x³ – x – x = 0$
$10x³ – 2x = 0$
$2x. ( 5x² – 1) = 0$
\(\left[ \begin{array}{l}2x = 0 \\5x² – 1 = 0\end{array} \right.\)
\(\left[ \begin{array}{l}x=0\\5x² = 1\end{array} \right.\)
\(\left[ \begin{array}{l}x=0\\x²=\dfrac{1}{5}\end{array} \right.\)
\(\left[ \begin{array}{l}x=2\\x=±\dfrac{√5}{5}\end{array} \right.\)
$10x^3-x=x$
$\Leftrightarrow 10x^3-2x=0$
$\Leftrightarrow 2x(5x^2-1)=0$
– TH1: $2x=0\Leftrightarrow x=0$
– TH2: $5x^2-1=0$
$\Leftrightarrow 5x^2=1$
$\Leftrightarrow x^2=\frac{1}{5}$
$\Leftrightarrow x=\pm \frac{1}{\sqrt5}$
Vậy $S= \{ 0; \pm \frac{1}{\sqrt5}\}$