Подстановка условия
[src]sin(pi/4 + a) - sin(pi/4 - a) при a = 1/2
sin(pi/4 + a) - sin(pi/4 - a)
−sin(−a+4π)+sin(a+4π) sin(pi/4 + (1/2)) - sin(pi/4 - (1/2))
−sin(−(1/2)+4π)+sin((1/2)+4π) sin(pi/4 + 1/2) - sin(pi/4 - 1/2)
−sin(−21+4π)+sin(21+4π) -cos(1/2 + pi/4) + sin(1/2 + pi/4)
−cos(21+4π)+sin(21+4π)