Подстановка условия
[src]sin(a + b) - sin(a - b) при a = -1/2
$$- \sin{\left (a - b \right )} + \sin{\left (a + b \right )}$$
sin((-1/2) + b) - sin((-1/2) - b)
$$- \sin{\left ((-1/2) - b \right )} + \sin{\left ((-1/2) + b \right )}$$
sin(-1/2 + b) - sin(-1/2 - b)
$$- \sin{\left (- b - \frac{1}{2} \right )} + \sin{\left (b - \frac{1}{2} \right )}$$
sin(1/2 + b) + sin(-1/2 + b)
$$\sin{\left (b - \frac{1}{2} \right )} + \sin{\left (b + \frac{1}{2} \right )}$$