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import math

def bisection(function, a, b): # finds where the function becomes 0 in [a,b] using bolzano

start = a

end = b

if function(a) == 0: # one of the a or b is a root for the function

return a

elif function(b) == 0:

return b

elif function(a) * function(b) > 0: # if none of these are root and they are both positive or negative,

# then his algorithm can't find the root

print("couldn't find root in [a,b]")

return

else:

mid = (start + end) / 2

while abs(start - mid) > 0.0000001: # until we achieve precise equals to 10^-7

if function(mid) == 0:

return mid

elif function(mid) * function(start) < 0:

end = mid

else:

start = mid

mid = (start + end) / 2

return mid

def f(x):

return math.pow(x, 3) - 2*x - 5

print(bisection(f, 1, 1000))

Sunbelt Computer Software