Для решения данного задания необходимо воспользоваться формулами преобразования суммы и разности синусов.
1) sin(3π/8) + sin(π/8) = 2 * sin((3π/8 + π/8)/2) * cos((3π/8 - π/8)/2) = 2 * sin(4π/16) * cos(2π/16) = 2 * sin(π/4) * cos(π/8) = 2 * (√2/2) * cos(π/8) = √2 * cos(π/8)
2) sin(7π/10) - sin(3π/10) = 2 * cos((7π/10 + 3π/10)/2) * sin((7π/10 - 3π/10)/2) = 2 * cos(10π/20) * sin(4π/20) = 2 * cos(π/2) * sin(π/5) = 2 * 0 * sin(π/5) = 0
Ответ: sin(3π/8) + sin(π/8) = √2 * cos(π/8), sin(7π/10) - sin(3π/10) = 0