cos(x)+cos(2*x)+cos(6*x)+cos(7*x) если x=1/3 (упростите выражение)

$$cos{left (x right )} + cos{left (2 x right )} + cos{left (6 x right )} + cos{left (7 x right )}$$

$$cos{left (x right )} + cos{left (2 x right )} + cos{left (6 x right )} + cos{left (7 x right )}$$

cos((1/3)) + cos(2*(1/3)) + cos(6*(1/3)) + cos(7*(1/3))

$$cos{left ((1/3) right )} + cos{left (2 (1/3) right )} + cos{left (6 (1/3) right )} + cos{left (7 (1/3) right )}$$

cos(1/3) + cos(2/3) + cos(6/3) + cos(7/3)

$$cos{left (frac{7}{3} right )} + cos{left (frac{6}{3} right )} + cos{left (frac{2}{3} right )} + cos{left (frac{1}{3} right )}$$

cos(2) + cos(1/3) + cos(2/3) + cos(7/3)

$$cos{left (frac{7}{3} right )} + cos{left (2 right )} + cos{left (frac{2}{3} right )} + cos{left (frac{1}{3} right )}$$

cos(x) + cos(2*x) + cos(6*x) + cos(7*x)

2 6 7 2 6 5 2 4 2 6 2 4 3 4
cos (x) + cos (x) + cos (x) – sin (x) – sin (x) – 21*cos (x)*sin (x) – 15*cos (x)*sin (x) – 7*sin (x)*cos(x) + 15*cos (x)*sin (x) + 35*cos (x)*sin (x) + cos(x)

$$- 7 sin^{6}{left (x right )} cos{left (x right )} – sin^{6}{left (x right )} + 35 sin^{4}{left (x right )} cos^{3}{left (x right )} + 15 sin^{4}{left (x right )} cos^{2}{left (x right )} – 21 sin^{2}{left (x right )} cos^{5}{left (x right )} – 15 sin^{2}{left (x right )} cos^{4}{left (x right )} – sin^{2}{left (x right )} + cos^{7}{left (x right )} + cos^{6}{left (x right )} + cos^{2}{left (x right )} + cos{left (x right )}$$