\[\frac{d[A]}{dt}=-k_1*[A]^2\]

A=1.0
B=0
P=0
k1=0.1
k2=0.3
k3=0.2
dt=0.1
t=0

AA=c()
tt=c()
PP=c()
BB=c()

while(t<50){
  AA=c(AA,A)
  PP=c(PP,P)
  BB=c(BB,B)
  tt=c(tt,t)
  
  dA=-k1*A*dt+k2*B*dt
  dB=k1*A*dt-k2*B*dt-k3*B*dt
  dP=k3*P*dt
  
  A=A+dA
  B=B+dB
  P=P+dP
  t=t+dt
}

plot(tt,AA,type="l",col="blue",ylim=c(0,1.1),xlab="t(min)",ylab="[A]",main="Cinética de segundo Orden")
lines(tt,BB,type="l",col="green")
lines(tt,PP,type="l",col="red")