Python Forum

Hello, I have an equation and need to plot a graph using the Euler method, the code looks like this:

h = 0.01
x = [0.0]
y = [0]
n = int(30/h)

def f(y,x):
    eq = #something
     return #something

for i in range (0,n):
    xn = (i+1)*h
    yn = y[i] + f(y[i],x[i])*h
    x.append(xn)
    y.append(yn)
    #print (x[i],y[i])
    
    
plt.plot(x,y)
plt.xlabel("Time(t)")
plt.ylabel("Concentration(Cs)")
plt.title("Concentration by Time")
plt.show()

But I have an equation, this one:

10(105 + log(900)) -5*t = S^2 /2 +20S +20log(S)

So when t = 0, S = 30. So I need to plot the values of S as the time increase.

Any help how to solve the equation?? In fact, I need anything that use the euler method that allows me to plot the graph.

Thanks in advance!

See this example: https://matplotlib.org/users/pyplot_tutorial.html

It might help to say what do you mean with "plotting graph using euler method" - euler method usually means numerical method to solve first order ODE - and if you mean this method, then solving ODE and plotting result are two rather separate things.

Anyway your equation is not a differential equation, you can transform it to an explicit form as t = f(S) and then straigtly plot it with matplotlib as Larz60+ suggested. And if you instist on using implicit equation, there is plot_implicit() function in sympy.plotting.