各位大佬帮忙看看，我这个Table循环是不是哪里写错了，为啥算不出答案
f = Subscript[a,
1] (Subscript[P, 1]^2 + Subscript[P, 2]^2 + Subscript[P, 3]^2) +
Subscript[a,
11] (Subscript[P, 1]^4 + Subscript[P, 2]^4 + Subscript[P, 3]^4) +
Subscript[a,
12] (Subscript[P, 1]^2*Subscript[P, 2]^2 +
Subscript[P, 2]^2*Subscript[P, 3]^2 +
Subscript[P, 1]^2*Subscript[P, 3]^2) +
Subscript[a,
111] (Subscript[P, 1]^6 + Subscript[P, 2]^6 + Subscript[P, 3]^6) +
Subscript[a,
112] (Subscript[P, 1]^2*(Subscript[P, 2]^4 + Subscript[P, 3]^4) +
Subscript[P, 2]^2 (Subscript[P, 1]^4 + Subscript[P, 3]^4) +
Subscript[P, 3]^2 (Subscript[P, 1]^4 + Subscript[P, 2]^4)) +
Subscript[a, 123]*Subscript[P, 1]^2*Subscript[P, 2]^2*Subscript[P,
3]^2 + Subscript[a,
1111] (Subscript[P, 1]^8 + Subscript[P, 2]^8 + Subscript[P,
3]^8) + Subscript[a,
1122] (Subscript[P, 1]^4*Subscript[P, 2]^4 +
Subscript[P, 2]^4*Subscript[P, 3]^4 +
Subscript[P, 1]^4*Subscript[P, 3]^4) +
Subscript[a,
1112] (Subscript[P, 1]^6*(Subscript[P, 2]^2 + Subscript[P, 3]^2) +
Subscript[P, 2]^6*(Subscript[P, 1]^2 + Subscript[P, 3]^2) +
Subscript[P, 3]^6*(Subscript[P, 1]^2 + Subscript[P, 2]^2)) +
Subscript[a,
1123] (Subscript[P, 1]^4*Subscript[P, 2]^2*Subscript[P, 3]^2 +
Subscript[P, 1]^2*Subscript[P, 2]^4*Subscript[P, 3]^2 +
Subscript[P, 1]^2*Subscript[P, 2]^2*Subscript[P, 3]^4);
Subscript[a, 1] = 4.124*10^5*(T - 115);
Subscript[a, 11] = -2.097*10^8;
Subscript[a, 12] = 7.974*10^8;
Subscript[a, 111] = 1.294*10^9;
Subscript[a, 112] = -1.950*10^9;
Subscript[a, 123] = -2.500*10^9;
Subscript[a, 1111] = 3.863*10^10;
Subscript[a, 1112] = 2.529*10^10;
Subscript[a, 1122] = 1.637*10^10;
Subscript[a, 1123] = 1.367*10^10;
Table[
{p = NSolve[{D[f, Subscript[P, 1]] == 0, D[f, Subscript[P, 2]] == 0,
D[f, Subscript[P, 3]] == 0}, {Subscript[P, 1], Subscript[P, 2],
Subscript[P, 3]}, Reals];
n = Flatten[Position[f /. p, Min[f /. p]]][[1]];
Polar = (Subscript[P, 1]^2 + Subscript[P, 2]^2 + Subscript[P,
3]^2)^(1/2); ans = Polar /. p[[n]];}, {T, 0, 10}]

算出来了，但是你加了分号（CompoundExpression），所以返回了Null。