Phương trình lượng giác cơ bản

$S=\left\{\dfrac{\pi}{2}+k\pi\mid k\in\mathbb{Z}\right\}$.

$S=\left\{\dfrac{\pi}{2}+k2\pi\mid k\in\mathbb{Z}\right\}$.

$S=\{k\pi\mid k\in\mathbb{Z}\}$.

$S=\{k2\pi\mid k\in\mathbb{Z}\}$.

$S=\left\{\dfrac{\pi}{2}+k\pi\mid k\in\mathbb{Z}\right\}$.

$S=\{k\pi\mid k\in\mathbb{Z}\}$.

$S=\left\{\dfrac{\pi}{2}+k2\pi\mid k\in\mathbb{Z}\right\}$.

$S=\{k2\pi\mid k\in\mathbb{Z}\}$.

$S=\left\{\dfrac{\pi}{2}+k2\pi\mid k\in\mathbb{Z}\right\}$.

$S=\left\{\dfrac{\pi}{2}+k\pi\mid k\in\mathbb{Z}\right\}$.

$S=\{k2\pi\mid k\in\mathbb{Z}\}$.

$S=\{k\pi\mid k\in\mathbb{Z}\}$.

$S=\left\{\dfrac{\pi}{2}+k\pi\mid k\in\mathbb{Z}\right\}$.

$S=\{k2\pi\mid k\in\mathbb{Z}\}$.

$S=\left\{\dfrac{\pi}{2}+k2\pi\mid k\in\mathbb{Z}\right\}$.

$S=\{k\pi\mid k\in\mathbb{Z}\}$.