(a^2+1) (a^5+2)
((a^2+1) a^3+2) a^2+2
1/4 (a+2^(1/5)) (a^2+1) (2 a^2+(-2^(1/5)-2^(1/5) sqrt(5)) a+2 2^(2/5)) (2 a^2+(2^(1/5) sqrt(5)-2^(1/5)) a+2 2^(2/5))
a = -2^(1/5)
a = -i
a = i
a = (-2)^(1/5)
a = -(-1)^(2/5) 2^(1/5)
a = (-1)^(3/5) 2^(1/5)
d/da(a^7+a^5+2 a^2+2) = a (7 a^5+5 a^3+4)
integral (2+2 a^2+a^5+a^7) da = a^8/8+a^6/6+(2 a^3)/3+2 a+constant
min{a^7+a^5+2 a^2+2} = 2 at a = 0