Question

Tìm tập xác định của các Hàm số sau

a) y = cot5x

b) y = tan6x

d) y = cot(3x-\(\dfrac{\pi}{6}\))

e) y = cot(4x-\(\dfrac{\pi}{3}\))

Answer 1

ĐKXĐ:

a.

\(sin5x\ne0\Leftrightarrow5x\ne k\pi\Rightarrow x\ne\dfrac{k\pi}{5}\)

b.

\(cos6x\ne0\Leftrightarrow6x\ne\dfrac{\pi}{2}+k\pi\Rightarrow x\ne\dfrac{\pi}{12}+\dfrac{k\pi}{6}\)

d.

\(sin\left(3x-\dfrac{\pi}{6}\right)\ne0\Leftrightarrow3x-\dfrac{\pi}{6}\ne k\pi\Rightarrow x\ne\dfrac{\pi}{18}+\dfrac{k\pi}{3}\)

e.

\(sin\left(4x-\dfrac{\pi}{3}\right)\ne0\Leftrightarrow4x-\dfrac{\pi}{3}\ne k\pi\Rightarrow x\ne\dfrac{\pi}{12}+\dfrac{k\pi}{4}\)