How can $2\mathrm{cos}(x-\frac{\pi}{2})=-2\mathrm{sin}(x-\frac{\pi}{2})$

I know that $\mathrm{cos}(-x)=\mathrm{cos}(x)$ and that $\mathrm{cos}({\displaystyle \frac{\pi}{2}}-x)=\mathrm{sin}(x)$

I know that $\mathrm{cos}(-x)=\mathrm{cos}(x)$ and that $\mathrm{cos}({\displaystyle \frac{\pi}{2}}-x)=\mathrm{sin}(x)$