r=x^8 - x^6 + x^4 - x^2 + 1 q= (x^12 - 2*x^11 + x^10 + x^2 + 2*x + 1)/ 4 P= x^6 - 2*x^5 + 7*x^4 - 10*x^3 + 13*x^2 - 10*x + 4 v= x-1/x