#include<cmath>
height = (distance * tan(angle)) - (gravity * pow(distance, 2)) /2  * pow(speed * cos(angle), 2);

I know height = distance * tan(angle) - (gravity * distance^2) /2 *( speed * cos(angle))^2

#include<cmath>
height = (distance * tan(angle)) - (gravity * pow(distance, 2)) /2  * pow(speed * cos(angle), 2);

#include <iostream>
#include <cmath>
using namespace std;
 
// This program is to  calculate the trajectories of projectiles and how the initial speed and 
// angle from the horizontal affect the distance the projectile will travel on different planets 
// and satellites.
//
//********************************************************************
//
//Example interaction with the user: 
 
//Trajectory Plotter!
//Enter a speed of launch (mps): 200
//Enter the angle of launch (in degrees): 35
//Speed = 200.00 mps, Angle = 35.00 degrees = 0.61 radians
 
//Distance travelled on Earth = 3831.57 m,  max height = 670.72 m
//Distance travelled on Mars = 9970.21 m,  max height = 1745.30 m
//Distance travelled on the Moon = 23202.29 m,  max height = 4061.60 m
 
//Maximum distance traveled = 23202.29
//Maximum height reached = 4061.60
//For Earth, the 5 points of the parabola would be:
// x0, y0 (0.00, 0.00)
// x1, y1 (957.89, 503.04)
// x2, y2 (1915.79, 670.72)
// x3, y3 (2873.68, 503.04)
// x4, y4 (3831.57, 0.00)
//
//********************************************************************
 
 
double angtorad (double angle, double pi);
double distance_earth (double angle, int mps, double earth_gravity);
double distance_moon (double angle, int mps, double moon_gravity);
double distance_mars (double angle, int mps, double mars_gravity);
double height_earth (double radian, int mps, double earth_gravity, double earthx);
double height_mars (double radian, int mps, double mars_gravity, double marsx);
double height_moon (double radian, int mps, double moon_gravity, double moonx);
int main ()
{
	int mps;
	double angle;
 
	cout << " ***  Program 3 Planetary Trajectory Simulator  *** " << endl;
	cout << endl;
	cout << " Enter the speed of launch (mps)	";
	cin >> mps;
	cout << " Enter the angle of launch (degrees)	"	;
	cin >> angle;
	cout << endl;
 
	double pi =  3.1415927;
	double radian = pi * ( angle / 180);
	double earth_gravity = 9.81;
	double moon_gravity = 1.62;
	double mars_gravity = 3.69;
	double earthx = distance_earth (angtorad(angle,pi),mps,earth_gravity);
	double marsx = distance_mars (angtorad(angle,pi),mps,mars_gravity);
	double moonx = distance_moon (angtorad(angle,pi),mps,moon_gravity);
 
	cout << " You have entered " << mps << " mps for the speed and " << angle << " degrees for the angle." << endl << endl;
	cout << " " << angle << " degrees is equal to " << angtorad(angle, pi) << " radian(s)." << endl << endl << endl;
	cout << " The distance traveled on Earth = " << distance_earth (angtorad(angle,pi),mps,earth_gravity) << " meters --";
	cout << " Max Height = " << height_earth (angtorad(angle,pi), mps, earth_gravity, earthx) << endl;
	cout << " The distance traveled on Mars = " << distance_mars (angtorad(angle,pi),mps,mars_gravity) << " meters -- ";
	cout << " Max Height = " << height_mars (angtorad(angle,pi), mps, mars_gravity, marsx) << endl;
	cout << " The distance traveled on The Moon = " << distance_moon (angtorad(angle,pi),mps,moon_gravity)<< " meters ";
	cout << " Max Height = " << height_moon (angtorad(angle,pi), mps, moon_gravity, moonx) << endl;
 
return 0;
}
double angtorad (double angle, double pi)
{
	double radian;
	radian =  pi * (angle / 180);
	return radian;
}
double distance_earth (double angle, int mps, double earth_gravity)
{
	double earth_distance;
	earth_distance =  sin(angle + angle)*(mps*mps) / earth_gravity;
	return earth_distance;
}
double distance_moon (double angle, int mps, double moon_gravity)
{
	double moon_distance;
	moon_distance =  sin(angle + angle)*(mps*mps) / moon_gravity;
	return moon_distance;
}
double distance_mars (double angle, int mps, double mars_gravity)
{
	double mars_distance;
	mars_distance = sin(angle + angle)*(mps*mps) / mars_gravity;
	return mars_distance;
}
double height_earth (double radian, int mps, double earth_gravity, double earthx)
{
	double max_height_earth;
	max_height_earth = (earthx*(tan(radian)))-((earth_gravity*(earthx*earthx)) / (2*((mps*(cos(radian)))*(mps*(cos(radian))))));
	return max_height_earth;
}
double height_mars (double radian, int mps, double mars_gravity, double marsx)
{
	double max_height_mars;
	max_height_mars = (marsx*(tan(radian)))-((mars_gravity*(marsx*marsx)) / (2*((mps*(cos(radian)))*(mps*(cos(radian))))));
	return max_height_mars;
}
double height_moon (double radian, int mps, double moon_gravity, double moonx)
{
	double max_height_moon;
	max_height_moon = (moonx*(tan(radian)))-((moon_gravity*(moonx*moonx)) / (2*((mps*(cos(radian)))*(mps*(cos(radian))))));
	return max_height_moon;