f(a,b) = 2 ∫<0,1>[x^4+(a^2+2b^2)x^2+b^4]dx + 0= 2[x^5/5+(a^2+2b^2)x^3/3+b^4x]<0,1> = 2[1/5+(1/3)(a^2+2b^2)+b^4]= 2/5+(2/3)a^2+(4/3)b^2+2b^4∂f/∂a = (4/3)a, ∂f/∂b = (8/3)b+8b^3
