matploltib_latex

import numpy as np 
import matplotlib.pyplot as plt 
import sympy as sb

x = sb.Symbol('x')
xx = np.linspace(0,1,1000)

plt.rcParams["font.size"] = 12
plt.rcParams['text.usetex'] = True

plt.figure(figsize=(6,6)) 

for i in range(4):
    f   = sb.sin((i+1)*sb.pi*x)
    ff  = sb.lambdify(x,f) 

    plt.subplot(2,2,i+1)
    plt.title('$'+'f_{%d}(x) = ' % (i+1) + sb.latex(f)+'$')

    plt.plot(xx,ff(xx))
    
plt.tight_layout()
plt.subplots_adjust(top=0.85)

txt = r'$f_i(x) = \sin(i \pi x)$'
plt.figtext(0.5,0.95,txt,fontsize=15,ha='center',va='center')
plt.savefig('test.png')