Giúp mình với ạ. ….

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Giúp mình với ạ. ….

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Giúp mình với ạ. ….
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Môn Toán Jezebel 4 years 2020-11-13T19:22:02+00:00 2020-11-13T19:22:02+00:00 2 Answers 54 views 0

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Captcha* Giải phương trình 1 ẩn: x + 2 - 2(x + 1) = -x . Hỏi x = ? ( )

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Nem · Answer 1 · 2020-11-13T19:23:27+00:00

Nem

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2020-11-13T19:23:27+00:00 November 13, 2020 at 7:23 pm

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`ĐK: x ne π/2 + kπ`

`PT`

`=> cos² x – sin x.cos x = 1`

`<=> -(1 – cos² x) – sin x.cos x = 0`

`<=> – (sin² x + sin x.cos x) = 0`

`<=> sin x(sin x + cos x) = 0`

`<=>` $[\begin{array}{l} s i n x = 0 \\ s i n x + c o s x = 0 \end{array}$

`<=>` $[\begin{array}{l} x = k π \\ c o s x = s i n (- x) \end{array}$

`<=>` $[\begin{array}{l} x = k π \\ c o s x = c o s (\frac{π}{2} + x) \end{array}$

`<=>` $[\begin{array}{l} x = k π \\ x = - \frac{π}{2} - x + k 2 π \\ x = \frac{π}{2} + x + k 2 π \end{array}$

`<=>` $[\begin{array}{l} x = k π \\ x = - \frac{π}{4} + k π \end{array}$ `( k ∈ ZZ)`

Sigrid · Answer 2 · 2020-11-13T19:23:39+00:00

Sigrid

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2020-11-13T19:23:39+00:00 November 13, 2020 at 7:23 pm

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