3 Вычислите sin a, cos a, tg a и ctg а для заданного значения угла: а) 45; б) 210; B) 5π/4; Г) 7π/6.

1. а) 45°:
   • \(\sin 45° = \frac{\sqrt{2}}{2}\)
   • \(\cos 45° = \frac{\sqrt{2}}{2}\)
   • \(\tan 45° = 1\)
   • \(\cot 45° = 1\)
2. б) 210°:
   • \(\sin 210° = -\frac{1}{2}\)
   • \(\cos 210° = -\frac{\sqrt{3}}{2}\)
   • \(\tan 210° = \frac{\sqrt{3}}{3}\)
   • \(\cot 210° = \sqrt{3}\)
3. в) \(\frac{5\pi}{4}\):
   • \(\sin \frac{5\pi}{4} = -\frac{\sqrt{2}}{2}\)
   • \(\cos \frac{5\pi}{4} = -\frac{\sqrt{2}}{2}\)
   • \(\tan \frac{5\pi}{4} = 1\)
   • \(\cot \frac{5\pi}{4} = 1\)
4. г) \(\frac{7\pi}{6}\):
   • \(\sin \frac{7\pi}{6} = -\frac{1}{2}\)
   • \(\cos \frac{7\pi}{6} = -\frac{\sqrt{3}}{2}\)
   • \(\tan \frac{7\pi}{6} = \frac{\sqrt{3}}{3}\)
   • \(\cot \frac{7\pi}{6} = \sqrt{3}\)

Ответ: значения тригонометрических функций для каждого угла указаны выше.