One of the founders of Foursquare is Dennis Crowley. The other is Naveen Selvadurai. I know you didn't ask for both but I wanted to give them to you just in case. I hope this helps! (:
MCSE is a Microsoft Certified Solutions Expert.
def dx(fn, x, delta=0.001):
return (fn(x+delta) - fn(x))/delta
def solve(fn, value, x=0.5, maxtries=1000, maxerr=0.00001):
for tries in xrange(maxtries):
err = fn(x) - value
if abs(err) < maxerr:
return x
slope = dx(fn, x)
x -= err/slope
raise ValueError('no solution found')
