Factor polynomial x^8-2*x

  /    7 ___\ /    7 ___    /pi\     7 ___    /pi\\ /    7 ___    /pi\     7 ___    /pi\\ /      7 ___    /2*pi\     7 ___    /2*pi\\ /      7 ___    /2*pi\     7 ___    /2*pi\\ /    7 ___    /3*pi\     7 ___    /3*pi\\ /    7 ___    /3*pi\     7 ___    /3*pi\\
x*\x - \/ 2 /*|x + \/ 2 *cos|--| + I*\/ 2 *sin|--||*|x + \/ 2 *cos|--| - I*\/ 2 *sin|--||*|x + - \/ 2 *cos|----| + I*\/ 2 *sin|----||*|x + - \/ 2 *cos|----| - I*\/ 2 *sin|----||*|x + \/ 2 *cos|----| + I*\/ 2 *sin|----||*|x + \/ 2 *cos|----| - I*\/ 2 *sin|----||
              \             \7 /              \7 // \             \7 /              \7 // \               \ 7  /              \ 7  // \               \ 7  /              \ 7  // \             \ 7  /              \ 7  // \             \ 7  /              \ 7  //

$$x \left(x - \sqrt[7]{2}\right) \left(x + \left(\sqrt[7]{2} \cos{\left(\frac{\pi}{7} \right)} + \sqrt[7]{2} i \sin{\left(\frac{\pi}{7} \right)}\right)\right) \left(x + \left(\sqrt[7]{2} \cos{\left(\frac{\pi}{7} \right)} - \sqrt[7]{2} i \sin{\left(\frac{\pi}{7} \right)}\right)\right) \left(x + \left(- \sqrt[7]{2} \cos{\left(\frac{2 \pi}{7} \right)} + \sqrt[7]{2} i \sin{\left(\frac{2 \pi}{7} \right)}\right)\right) \left(x + \left(- \sqrt[7]{2} \cos{\left(\frac{2 \pi}{7} \right)} - \sqrt[7]{2} i \sin{\left(\frac{2 \pi}{7} \right)}\right)\right) \left(x + \left(\sqrt[7]{2} \cos{\left(\frac{3 \pi}{7} \right)} + \sqrt[7]{2} i \sin{\left(\frac{3 \pi}{7} \right)}\right)\right) \left(x + \left(\sqrt[7]{2} \cos{\left(\frac{3 \pi}{7} \right)} - \sqrt[7]{2} i \sin{\left(\frac{3 \pi}{7} \right)}\right)\right)$$

((((((x*(x - 2^(1/7)))*(x + 2^(1/7)*cos(pi/7) + i*2^(1/7)*sin(pi/7)))*(x + 2^(1/7)*cos(pi/7) - i*2^(1/7)*sin(pi/7)))*(x - 2^(1/7)*cos(2*pi/7) + i*2^(1/7)*sin(2*pi/7)))*(x - 2^(1/7)*cos(2*pi/7) - i*2^(1/7)*sin(2*pi/7)))*(x + 2^(1/7)*cos(3*pi/7) + i*2^(1/7)*sin(3*pi/7)))*(x + 2^(1/7)*cos(3*pi/7) - i*2^(1/7)*sin(3*pi/7))