cos(2*x-3*pi*1/4)*cos(7*pi*1/4+4*x) если x=1/4 (упростите выражение)

$$cos{left (2 x – frac{3 pi}{4} right )} cos{left (4 x + frac{7 pi}{4} right )}$$

$$cos{left (2 x – frac{3 pi}{4} right )} cos{left (4 x + frac{7 pi}{4} right )}$$

cos(2*(1/4) – 3*pi/4)*cos((7*pi)/4 + 4*(1/4))

$$cos{left (2 (1/4) – frac{3 pi}{4} right )} cos{left (4 (1/4) + frac{7 pi}{4} right )}$$

cos(2/4 – 3*pi/4)*cos((7*pi)/4 + 4/4)

$$cos{left (frac{4}{4} + frac{7 pi}{4} right )} cos{left (- frac{3 pi}{4} + frac{2}{4} right )}$$

-cos(1/2 + pi/4)*sin(1 + pi/4)

$$- sin{left (frac{pi}{4} + 1 right )} cos{left (frac{1}{2} + frac{pi}{4} right )}$$

$$- sin{left (4 x + frac{pi}{4} right )} cos{left (2 x + frac{pi}{4} right )}$$

cos(2*x – 3*pi/4)*cos((7*pi)/4 + 4*x)

$$- sin{left (frac{1}{4} left(16 x + piright) right )} cos{left (frac{1}{4} left(8 x + piright) right )}$$

$$cos{left (frac{1}{4} left(8 x – 3 piright) right )} cos{left (frac{1}{4} left(16 x + 7 piright) right )}$$

/ pi / pi
-cos|2*x + –|*sin|4*x + –|
4 / 4 /

$$- sin{left (4 x + frac{pi}{4} right )} cos{left (2 x + frac{pi}{4} right )}$$

$$- frac{1}{2} sin{left (2 x right )} – frac{1}{2} cos{left (6 x right )}$$

/ pi / pi
-cos|2*x + –|*sin|4*x + –|
4 / 4 /

$$- sin{left (4 x + frac{pi}{4} right )} cos{left (2 x + frac{pi}{4} right )}$$

/ pi /7*pi
-cos|2*x + –|*cos|—- + 4*x|
4 / 4 /

$$- cos{left (2 x + frac{pi}{4} right )} cos{left (4 x + frac{7 pi}{4} right )}$$

/ pi / pi
-cos|2*x + –|*sin|4*x + –|
4 / 4 /

$$- sin{left (4 x + frac{pi}{4} right )} cos{left (2 x + frac{pi}{4} right )}$$

/ ___ ___ / ___ ___
|/ 2 *cos(4*x) / 2 *sin(4*x)| |/ 2 *sin(2*x) / 2 *cos(2*x)|
|————– + ————–|*|————– – ————–|
2 2 / 2 2 /

$$left(frac{sqrt{2}}{2} sin{left (2 x right )} – frac{sqrt{2}}{2} cos{left (2 x right )}right) left(frac{sqrt{2}}{2} sin{left (4 x right )} + frac{sqrt{2}}{2} cos{left (4 x right )}right)$$