% Problem 9.4

Variable x'', theta'

Constant vb = 15 m/s 
Constant co = 0.1, c1 = 0.098, c2 = -0.00049

eq[1] = x'-vb*cos(theta)
% y' = 0 to go in straight line
eq[2] = vb*sin(theta) - (co + c1*x + c2*x^2)

SolveSetInput(Evaluate(eq,x=0), x' = 5 m/s, theta = 20 deg)

Input x = 0 m, tFinal = 13.76 sec
Output t sec, x m, theta deg

ODE(dt(eq), x'', theta')