I have following function 4/((1 + v1(h))*(1 + v2(h))):

```
Ones = Function(h,
NIntegrate((1/(2*Pi))*
E^(-I*x)*(-h + Cos(x) - I Sin(x))/Sqrt(1 + h^2 - 2 h Cos(x)), {x,
0, 2 Pi}));
Ones2 = Function(h,
NIntegrate((1/(2*Pi))*
E^(I*x)*(-h + Cos(x) - I Sin(x))/Sqrt(1 + h^2 - 2 h Cos(x)), {x,
0, 2 Pi}));
Zeros = Function(h,
NIntegrate((1/(2*Pi))*(-h + Cos(x) - I Sin(x))/
Sqrt(1 + h^2 - 2 h Cos(x)), {x, 0, 2 Pi}));
v1 = Function(h,
Re(1/Sqrt(
2) ((Sqrt)(2 Zeros(h)^2 + Ones(h)^2 + Ones2(h)^2 +
Ones(h) Sqrt(
4 Zeros(h)^2 + Ones(h)^2 - 2 Ones(h)* Ones2(h) +
Ones2(h)^2) +
Ones2(h) Sqrt(
4 Zeros(h)^2 + Ones(h)^2 - 2 Ones(h)* Ones2(h) +
Ones2(h)^2)))));
v2 = Function(h,
Re(1/Sqrt(
2) ((Sqrt)(2 Zeros(h)^2 + Ones(h)^2 + Ones2(h)^2 -
Ones(h) Sqrt(
4 Zeros(h)^2 + Ones(h)^2 - 2 Ones(h)* Ones2(h) +
Ones2(h)^2) -
Ones2(h) Sqrt(
4 Zeros(h)^2 + Ones(h)^2 - 2 Ones(h)* Ones2(h) +
Ones2(h)^2)))));
Plot({4/((1 + v1(h))*(1 + v2(h)))}, {h, 0, 2},
PlotLegends -> Automatic)
```

However, when I try to use the following code to plot the derivative of this function, nothing shows up:

```
d1 = Function(h,
Re@Derivative(1)(Function(h, 4/((1 + v1(h))*(1 + v2(h)))))(h));
Plot(d1(h), {h, 0, 2})
```

How can I solve this problem?