(related to Proposition: Special Values for Real Sine, Real Cosine and Complex Exponential Function)
The zeros the real sine $\sin(x)=0$ are exactly the numbers $x=k\pi,$ and of the real cosine $\cos(x)=0$ are exactly the numbers $x=\left(k+\frac 12\right)\pi,$ in which $k\in\mathbb Z$ denotes an integer and $\pi$ denotes the $\pi$ constant. Formally,
$$\sin(x)=0\Longleftrightarrow x=k\pi,\quad k\in\mathbb Z.$$ $$\cos(x)=0\Longleftrightarrow x=\left(k+\frac 12\right)\pi,\quad k\in\mathbb Z.$$
Proofs: 1
Proofs: 1
