#includedouble angle_degrees = 90; double angle_radians = angle_degrees * M_PI / 180;
#includeIn this example, we use the built-in function `std::sin` (also defined in the `cmath` library) to calculate the sine of the angle. The package/library used in these examples is `cmath`, which is a standard library in C++ that provides mathematical functions and constants.double angle = M_PI/2; // 90 degrees in radians double sin_value = std::sin(angle);