help for projectile equation

how do I write first order equations for the two components of velocity and two components of position with x,y for matlab solver for the below equation... for projectile

r¨(t) = 1/m(-1/2ρcdA|r˙|r˙ − mg)

really appreciate if somebody could help me.

thanks

Answer 1

[Alan Stevens]

These are the equations (note that theta is measured from the horizontal, and is positive in the anticlockwise direction):

[Rose reeves]

Thank you so much... really appreciate.