r= x^20 - x^18 + x^16 - x^14 + x^12 - x^10 + x^8 - x^6 + x^4 - x^2 + 1 q= (x^24 - 2*x^23 + x^22 + x^2 + 2*x + 1)/ 4 P= x^10 - 2*x^9 + 11*x^8 - 18*x^7 + 43*x^6 - 54*x^5 + 70*x^4 - 60*x^3 + 41*x^2 - 18*x + 4 v= x-1/x