Найдите \(tg2x,\) если \(cosx=\frac{5}{8},\) \(\frac{3\pi}{4}<x<2\pi.\) \(-\frac{5\sqrt{39}}{7}\) \(\frac{5\sqrt{39}}{7}\) \(-\frac{5\sqrt{11}}{7}\) \(\frac{5\sqrt{11}}{7}\)
Задание

Найдите \(tg2x,\) если \(cosx=\frac{5}{8},\) \(\frac{3\pi}{4}\lt x\lt 2\pi.\)

  • \(-\frac{5\sqrt{39}}{7}\)
  • \(\frac{5\sqrt{39}}{7}\)
  • \(-\frac{5\sqrt{11}}{7}\)
  • \(\frac{5\sqrt{11}}{7}\)