Вычислите \(\frac{1-\ctg\alpha}{\tg\alpha-1}\) , если \(\sin\alpha=-\frac{24}{25}\) и \(\pi\lt \alpha\lt \frac{3\pi}{2}\) .

• \(\frac{7}{24}\)
• \(-\frac{24}{25}\)
• \(\frac{25}{24}\)
• \(\frac{24}{7}\)