Vjezbe #3

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Created on Tue Oct 22 08:18:14 2019

@author: student
"""

import numpy as np
import matplotlib.pyplot as plt

#def f(x):
#    return 2*x**2 - 4
#
#xl = float(input("Unesi lijevu granicu: "))
#xd = float(input("Unesi desnu granicu: "))
#epsilon = float(input("Unesi dopustenu gresku: "))
#
#x = np.linspace(xl, xd, 100)
#
#plt.plot(x, f(x),'r-')
#plt.axhline(color='black')
#
#maxiter = 100
#it = 0
#
#while it < maxiter:
#    xs = (xd+xl) * 0.5
#
#    error = np.abs(f(xs))
#
#    if error < epsilon:
#        print("Dopustena greska zadovoljena")
#        break
#    elif f(xs) * f(xd) < 0:
#        xl = xs
#    else:
#        xd = xs
#    it = it + 1
#    print (it, xs)
#
#print("Bisekcija x: ", xs)
#plt.plot(xs, 0, 'bo')

#def f(x):
#    return 2*x**2 - 4
#
#def f_der(x):
#    return 4*x

#x1 = float(input("Unesi pocetnu tocku: "))
#epsilon = float(input("Unesi dopustenu gresku: "))
#
#X = np.array([x1])
#maxit = 100
#it = 1
#
#while it < maxit:
#    Xi = X[-1] - f(X[-1]) / f_der(X[-1])
#    X = np.append(X, Xi)
#
#    error = np.abs(X[-1] - X[-2])
#    if error < epsilon:
#        break
#
#    it += 1
#
#print(it, X[-1])

import scipy.optimize as opt

#x0 = opt.fsolve(f, 2)
#print ("nultocka scipy: ", x0[0])


#def f(x):
#    return np.cos((x/2.2) -5.5) *5
#
#x = np.linspace(0, 24, 100)
#plt.plot(x, f(x), 'b-')
#plt.axhline(color = 'black')
#
#x0 = opt.fsolve(f, [1,8,14,20])
#print("nultocka: ", x0)
#plt.plot(x0, [0, 0, 0, 0], 'k*', label ='0*C')
#plt.legend()

def f(x):
    return 1250 * np.sin(x - 2) + 250 * x + 1100 - 1250

x = np.linspace(0,30,100)
plt.plot(x, f(x), 'r--')
plt.axhline(color='black')

vrijeme = opt.fsolve(f, 2)
print (vrijeme[0])