In [1]:
import numpy as np
import matplotlib.pyplot as plt
from IPython.display import display,Math
In [2]:
lst = [-4,5.5,1,2]

maxval = np.max(lst)
maxvalindx = np.argmax(lst)

lst[maxvalindx]
Out[2]:
5.5
In [3]:
minval = np.min(lst)
minvalindx = np.argmin(lst)

lst[minvalindx]
Out[3]:
-4
In [4]:
x = np.linspace(0,2*np.pi,20)
fx = -(np.cos(x) + np.sqrt(x))

fmax = np.max(fx)
fmaxidx = np.argmax(fx)
print(fmax, fmaxidx)

plt.plot(x,fx,'bo-')
plt.plot(x[fmaxidx],fmax,'rs')

plt.show()

-0.7388185920927908 9
In [5]:
x = np.linspace(-2,2,51)

fx = x**3 + x**4

fminidx = np.argmin(fx)

plt.plot(x,fx,'bs-')
plt.plot(x[fminidx],fx[fminidx],'rs')

plt.xlim([-1.2,.5])
plt.ylim([-.2,.2])
plt.show()

Exercise

In [6]:
display(Math('f(x) = -\\cos(x) - \\sqrt{x}'))
$\displaystyle f(x) = -\cos(x) - \sqrt{x}$
In [7]:
from scipy.signal import find_peaks

x = np.linspace(0,12*np.pi,213)
print(12*np.pi)

fx = -np.cos(x) - np.sqrt(x)

peaks = find_peaks(fx)
print(peaks)
print(peaks[0])

plt.plot(x,fx)
plt.plot(x[peaks[0]],fx[peaks[0]],'o')
plt.show()

37.69911184307752
(array([ 16,  52,  88, 123, 158, 194]), {})
[ 16  52  88 123 158 194]