Решение:

а) $$5\sin{\frac{\pi}{2}}+4\cos{0}-3\sin{\frac{3\pi}{2}}+\cos{\pi} = 5 \cdot 1 + 4 \cdot 1 - 3 \cdot (-1) + (-1) = 5 + 4 + 3 - 1 = 11$$

Ответ: 11

б) $$\sin{(-\pi)}-\cos{\frac{3\pi}{2}}+2\sin{2\pi}-\text{tg}{\pi} = 0 - 0 + 2 \cdot 0 - 0 = 0$$

Ответ: 0

в) $$3-\sin^2{\frac{\pi}{3}}+2\cos^2{\frac{\pi}{2}}-5\text{tg}^2{\frac{\pi}{4}} = 3 - (\frac{\sqrt{3}}{2})^2 + 2 \cdot 0^2 - 5 \cdot 1^2 = 3 - \frac{3}{4} + 0 - 5 = -2 - \frac{3}{4} = -2\frac{3}{4} = -2.75$$

Ответ: $$-2\frac{3}{4} = -2.75$$

г) $$3\sin^2{\frac{\pi}{2}}-4\text{tg}^2{\frac{\pi}{4}}-3\cos^2{\frac{\pi}{6}}+3\text{ctg}^2{\frac{\pi}{2}} = 3 \cdot 1^2 - 4 \cdot 1^2 - 3 \cdot (\frac{\sqrt{3}}{2})^2 + 3 \cdot 0^2 = 3 - 4 - 3 \cdot \frac{3}{4} + 0 = -1 - \frac{9}{4} = -1 - 2\frac{1}{4} = -3\frac{1}{4} = -3.25$$

Ответ: $$-3\frac{1}{4} = -3.25$$