Question

Giúp mik vs

Answer 1

`1)` H/s xđ `<=>cos 2x \ne 0<=>2x \ne \pi/2+k\pi<=>x \ne \pi/4+k\pi/2`  `(k in ZZ)`

   `=>TXĐ: D=R\\{\pi/4+k\pi/2|k in ZZ}`

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`2)` H/s xđ `<=>sin(x+\pi/3) \ne 0<=>x+\pi/3 \ne k\pi<=>x \ne -\pi/3+k\pi`  `(k in ZZ)`

  `=>TXĐ: D=R\\{-\pi/3+k\pi|k in ZZ}`

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`3)` H/s xđ `<=>cos(x+\pi/4) \ne 0<=>x+\pi/4 \ne \pi/2+k\pi<=>x \ne \pi/4+k\pi`  `(k in ZZ)`

   `=>TXĐ: D=R\\{\pi/4+k\pi|k in ZZ}`

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`4)` H/s xđ `<=>sin(2x-\pi/3) \ne 0<=>2x-\pi/3 \ne k\pi<=>x \ne \pi/6+k\pi/2`  `(k in ZZ)`

  `=>TXĐ: D=R\\{\pi/6+k\pi/2| k in ZZ}`

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`5)` H/s xđ `<=>sin x \ne 0<=>x \ne k\pi`  `(k in ZZ)`

   `=>TXĐ: D=R\\{k\pi|k in ZZ}`

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`6)` H/s xđ `<=>cos(2x-\pi/3) \ne 0<=>2x-\pi/3 \ne \pi/2+k\pi<=>x \ne [5\pi]/12+k\pi/2`  `(k in ZZ)`

   `=>TXĐ: D=R\\{[5\pi]/12+k\pi/2|k in ZZ}`