eq1:=diff(x(t),t)=vx(t);eq2:=diff(y(t),t)=vy(t);eq3:=diff(vx(t),t)=-alpha*sqrt(vx(t)^2+vy(t)^2)*vx(t);eq4:=diff(vy(t),t)=-g-alpha*sqrt(vx(t)^2+vy(t)^2)*vy(t);eqnset:={eq1,eq2,eq3,eq4,x(0)=0,y(0)=0,vx(0)=10,vy(0)=10};with(plots);g:=9.8;alpha:=1;nsoln:=dsolve(eqnset,{x(t),y(t),vx(t),vy(t)},numeric);odeplot(nsoln,[t,x(t)],0..2);odeplot(nsoln,[t,y(t)],0..2);odeplot(nsoln,[x(t),y(t)],0..0.85);alpha:=0.2;nsoln02:=dsolve(eqnset,{x(t),y(t),vx(t),vy(t)},numeric);odeplot(nsoln02,[t,y(t)],0..2);odeplot(nsoln02,[x(t),y(t)],0..1.35)