Дано
$$3 cos{left (a right )} – 3 cos{left (- a + 360 right )} + cos{left (- a + 90 right )} + cos{left (a + 90 right )}$$
Подстановка условия
$$3 cos{left (a right )} – 3 cos{left (- a + 360 right )} + cos{left (- a + 90 right )} + cos{left (a + 90 right )}$$
3*cos((1/3)) – 3*cos(360 – (1/3)) + cos(90 – (1/3)) + cos((1/3) + 90)
$$3 cos{left ((1/3) right )} – 3 cos{left (- (1/3) + 360 right )} + cos{left (- (1/3) + 90 right )} + cos{left ((1/3) + 90 right )}$$
3*cos(1/3) – 3*cos(360 – 1/3) + cos(90 – 1/3) + cos(1/3 + 90)
$$cos{left (frac{1}{3} + 90 right )} + cos{left (- frac{1}{3} + 90 right )} + – 3 cos{left (- frac{1}{3} + 360 right )} + 3 cos{left (frac{1}{3} right )}$$
-3*cos(1079/3) + 3*cos(1/3) + cos(269/3) + cos(271/3)
$$cos{left (frac{271}{3} right )} – 3 cos{left (frac{1079}{3} right )} + cos{left (frac{269}{3} right )} + 3 cos{left (frac{1}{3} right )}$$
Степени
$$3 cos{left (a right )} – 3 cos{left (a – 360 right )} + cos{left (a – 90 right )} + cos{left (a + 90 right )}$$
Численный ответ
3.0*cos(a) – 3.0*cos(360 – a) + cos(90 – a) + cos(a + 90)
Рациональный знаменатель
$$3 cos{left (a right )} – 3 cos{left (a – 360 right )} + cos{left (a – 90 right )} + cos{left (a + 90 right )}$$
Объединение рациональных выражений
$$3 cos{left (a right )} – 3 cos{left (a – 360 right )} + cos{left (a – 90 right )} + cos{left (a + 90 right )}$$
Общее упрощение
-3*cos(-360 + a) + 3*cos(a) + 2*cos(90)*cos(a)
$$2 cos{left (90 right )} cos{left (a right )} + 3 cos{left (a right )} – 3 cos{left (a – 360 right )}$$
Соберем выражение
$$3 cos{left (a right )} + cos{left (- a + 90 right )} – 3 cos{left (- a + 360 right )} + cos{left (a + 90 right )}$$
-3*cos(-360 + a) + 3*cos(a) + cos(-90 + a) + cos(90 + a)
$$3 cos{left (a right )} – 3 cos{left (a – 360 right )} + cos{left (a – 90 right )} + cos{left (a + 90 right )}$$
Общий знаменатель
-3*cos(360 – a) + 3*cos(a) + cos(90 + a) + cos(90 – a)
$$3 cos{left (a right )} + cos{left (- a + 90 right )} – 3 cos{left (- a + 360 right )} + cos{left (a + 90 right )}$$
Тригонометрическая часть
-3*cos(-360 + a) + 3*cos(a) + 2*cos(90)*cos(a)
$$2 cos{left (90 right )} cos{left (a right )} + 3 cos{left (a right )} – 3 cos{left (a – 360 right )}$$
Комбинаторика
-3*cos(-360 + a) + 3*cos(a) + cos(-90 + a) + cos(90 + a)
$$3 cos{left (a right )} – 3 cos{left (a – 360 right )} + cos{left (a – 90 right )} + cos{left (a + 90 right )}$$
Раскрыть выражение
3*cos(a) – 3*cos(360)*cos(a) – 3*sin(360)*sin(a) + 2*cos(90)*cos(a)
$$- 3 sin{left (360 right )} sin{left (a right )} + 2 cos{left (90 right )} cos{left (a right )} – 3 cos{left (360 right )} cos{left (a right )} + 3 cos{left (a right )}$$