#hledani korenu funkce f metodou regula falsi
import math

def regulaFalsi(f, a, b, maxiter=50):
    fa, fb = f(a), f(b)
    for i in range(maxiter):
        # approximation by secant, this form doesn't suffer from cancellation
        x_tmp = (a*fb-b*fa)/(fb-fa)
        fx_tmp = f(x_tmp)
        if fx_tmp*fa < 0:
            b, fb = x_tmp, fx_tmp
        else:
            a, fa = x_tmp, fx_tmp
        print(x_tmp,fx_tmp)
    return x_tmp

#vysetrovana funkce
f = lambda x: math.exp(x)-5.0*x*x

#pocatecni a,b zjisteny pohledem na graf funkce
print(regulaFalsi(f,-1.0,0.0))
print()
print(regulaFalsi(f,0.0,1.0))
print()
print(regulaFalsi(f,4.0,5.0))