NAG Library Manual, Mark 28.5
```/* nag::ad::d02bj Passive Example Program.
*/

#include <dco.hpp>
#include <iostream>

// Function which calls NAG AD routines.
// Solves the ODE for a projectile
//   y1' = tan(y3)
//   y2' = alpha * tan(y3) / y2 - beta * y2 / cos(y3)
//   y3' = alpha / y2^2
// until it hits the ground. x is the hit point.
template <typename T>
void func(const std::vector<T> &y0, const T &alpha, const T &beta, T &x);

int main()
{
std::cout << "nag::ad::d02bj Passive Example Program Results\n\n";

// Parameters
double alpha = -0.032, beta = -0.02;
// Initial condition
std::vector<double> y0{0.5, 0.5, 0.2 * nag_math_pi};
// Hit point
double x;

// Call NAG Lib functions
func(y0, alpha, beta, x);

// Print outputs
std::cout.setf(std::ios::scientific, std::ios::floatfield);
std::cout.precision(6);
std::cout << " Hit point = " << x << "\n\n";

return 0;
}

// function which calls NAG AD Library routines
template <typename T>
void func(const std::vector<T> &y0, const T &alpha, const T &beta, T &x)
{
Integer n  = y0.size();
Integer iw = 20 * n;
// Active variables
std::vector<T> w(iw), ruser{alpha, beta};
T              xinit = 0.0, xend = 10.0, tol = 1.0e-5;

const T &          x,
const T            y[],
T                  f[])
{
T alpha, beta;
alpha = ruser[0];
beta  = ruser[1];

f[0] = tan(y[2]);
f[1] = alpha * tan(y[2]) / y[1] + beta * y[1] / cos(y[2]);
f[2] = alpha / (y[1] * y[1]);
};

auto g = [](nag::ad::handle_t&, T const&, T const y[], T & z)
{
z = y[0];
};

// Create AD configuration data object
Integer           ifail = 0;