>>639-641

被積分函数は x^4･(1-x)^4 /(1+x^2) = x^6 -4x^5 +5x^4 -4x^2 +4 -4/(1+x^2),

　(左辺) = [ (1/7)x^7 -(2/3)x^6 +x^5 -(4/3)x^3 +4x -4arctan(x) ](x=0,1)
　= (1/7) -(2/3) +1 -(4/3) +4 -π
　= (22/7) - π,