Solve in real numbers the equation
[tex]|x+\sqrt{1-x^{2}}|=\sqrt{2}\left(2x^{2}-1\right)[/tex].
MM wrote:Solve in real numbers the equation
[tex]|x+\sqrt{1-x^{2}}|=\sqrt{2}\left(2x^{2}-1\right)[/tex].
MM wrote:Solve in real numbers the equation
[tex]|x+\sqrt{1-x^{2}}|=\sqrt{2}\left(2x^{2}-1\right)[/tex].
martosss wrote:Substitute [tex]x=cos\alpha, \alpha \in[0: ;\: \pi ][/tex]
[tex]Then\; |x+\sqrt{1-x^2}|=\sqrt{2}(2x^2-1) |cos\alpha +sin\alpha |=\sqrt{2}(2cos^2\alpha -1)[/tex]
[tex]|\N {\sqrt{2}}cos(\alpha -\frac{\pi}{4})|=\N {\sqrt{2}}cos(2\alpha )\ \alpha \in[0\: ;\: \frac{\pi}{4}]\cup [\frac{3\pi}{4}\: ;\: \pi][/tex]
1) [tex]\alpha \in [0\: ;\: \frac{\pi}{4}][/tex]
[tex]cos(\alpha -\frac{\pi}{4})=cos(2\alpha )\dots[/tex]
2. [tex]\alpha \in [\frac{3\pi}{4}\: ;\: \pi][/tex]
[tex]-cos(\alpha -\frac{\pi}{4})=cos(2\alpha )\dots[/tex]
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