Solve for x
x\in \begin{bmatrix}-\sqrt{2}-1,\sqrt{2}-1\end{bmatrix}
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2x^{2}+4x-2=0
To solve the inequality, factor the left hand side. Quadratic polynomial can be factored using the transformation ax^{2}+bx+c=a\left(x-x_{1}\right)\left(x-x_{2}\right), where x_{1} and x_{2} are the solutions of the quadratic equation ax^{2}+bx+c=0.
x=\frac{-4±\sqrt{4^{2}-4\times 2\left(-2\right)}}{2\times 2}
All equations of the form ax^{2}+bx+c=0 can be solved using the quadratic formula: \frac{-b±\sqrt{b^{2}-4ac}}{2a}. Substitute 2 for a, 4 for b, and -2 for c in the quadratic formula.
x=\frac{-4±4\sqrt{2}}{4}
Do the calculations.
x=\sqrt{2}-1 x=-\sqrt{2}-1
Solve the equation x=\frac{-4±4\sqrt{2}}{4} when ± is plus and when ± is minus.
2\left(x-\left(\sqrt{2}-1\right)\right)\left(x-\left(-\sqrt{2}-1\right)\right)\leq 0
Rewrite the inequality by using the obtained solutions.
x-\left(\sqrt{2}-1\right)\geq 0 x-\left(-\sqrt{2}-1\right)\leq 0
For the product to be ≤0, one of the values x-\left(\sqrt{2}-1\right) and x-\left(-\sqrt{2}-1\right) has to be ≥0 and the other has to be ≤0. Consider the case when x-\left(\sqrt{2}-1\right)\geq 0 and x-\left(-\sqrt{2}-1\right)\leq 0.
x\in \emptyset
This is false for any x.
x-\left(-\sqrt{2}-1\right)\geq 0 x-\left(\sqrt{2}-1\right)\leq 0
Consider the case when x-\left(\sqrt{2}-1\right)\leq 0 and x-\left(-\sqrt{2}-1\right)\geq 0.
x\in \begin{bmatrix}-\left(\sqrt{2}+1\right),\sqrt{2}-1\end{bmatrix}
The solution satisfying both inequalities is x\in \left[-\left(\sqrt{2}+1\right),\sqrt{2}-1\right].
x\in \begin{bmatrix}-\sqrt{2}-1,\sqrt{2}-1\end{bmatrix}
The final solution is the union of the obtained solutions.
Examples
Quadratic equation
{ x } ^ { 2 } - 4 x - 5 = 0
Trigonometry
4 \sin \theta \cos \theta = 2 \sin \theta
Linear equation
y = 3x + 4
Arithmetic
699 * 533
Matrix
\left[ \begin{array} { l l } { 2 } & { 3 } \\ { 5 } & { 4 } \end{array} \right] \left[ \begin{array} { l l l } { 2 } & { 0 } & { 3 } \\ { -1 } & { 1 } & { 5 } \end{array} \right]
Simultaneous equation
\left. \begin{cases} { 8x+2y = 46 } \\ { 7x+3y = 47 } \end{cases} \right.
Differentiation
\frac { d } { d x } \frac { ( 3 x ^ { 2 } - 2 ) } { ( x - 5 ) }
Integration
\int _ { 0 } ^ { 1 } x e ^ { - x ^ { 2 } } d x
Limits
\lim _{x \rightarrow-3} \frac{x^{2}-9}{x^{2}+2 x-3}