Python function help

Question

Please help! cannot figure this out for the life of me

Given the function f(x,n)= n**x(n-1)

5c. Using this function, calculate the rate of change of (((2^3 + 3^2)^4 -2^4)^2 + (3^4 – (6^2 + 3)^4)^3)^3

This is what I came up with in IDLE:

def function(x, n):
    return (n*(x**(n-1)))

assertEqual (
  function ((((
    function (2.0, 3.0))+(
      function (3.0, 2.0)), 4.0)-(
        function (2.0, 4.0)), 2.0)+((
          function (3.0, 4.0))-((
            function (6.0, 2.0))+(
              function (3.0, 1.0)), 4.0), 3.0), 3.0), 35994405888.0)

and after I save and run it, I get this message:

Traceback (most recent call last):
  File "C:\Users\Jonathan Cohen\Desktop\School\CISC 106\lab2.py", line 83, in <module>
    assertEqual (function ((((function (2.0, 3.0))+(function (3.0, 2.0)), 4.0)-(function (2.0, 4.0)), 2.0)+((function (3.0, 4.0))-((function (6.0, 2.0))+(function (3.0, 1.0)), 4.0), 3.0), 3.0), 35994405888.0)
TypeError: unsupported operand type(s) for -: 'tuple' and 'float'

Answer 1

(function(a, b), c) is a 2-tuple consisting of the result of function(a,b) and c.

If you want to represent (a^b)^c, you'd need something like function(function(a,b), c) (assuming function() computes its first parameter raised to the second.)

Answer 2

There are a few occurances of this, but here is the first one.

function ((((function (2.0, 3.0))+(function (3.0, 2.0)), 4.0)-(function (2.0, 4.0)), 2.0)+((function (3.0, 4.0))-((function (6.0, 2.0))+(function (3.0, 1.0)), 4.0), 3.0), 3.0)
           ((function (2.0, 3.0))+(function (3.0, 2.0)), 4.0)

The segment that I've blocked out, produces a tuple of (18.0, 4.0). You then try to do normal math on this, which fails.

---

In response to the comment, this particular segment would work better if you did the following:

function((function (2.0, 3.0))+(function (3.0, 2.0)), 4.0)

Answer 3

This starts off looking like calculus to me, but quickly goes off the rails.

Elementary differential calculus says that if you have a function:

then the first derivative with respect to the independent variable x is:

It looks to me like you're trying to evaluate something like this with Python, but the tuple expression you give makes no sense to me. Was there supposed to be an independent variable hidden in there somewhere?

Answer 4

So after two weeks of pulling my hair out trying to figure this out I think I finally got it. Thanks so much everybody, all your input really helped! I broke down each part and rewrote everything according to what you all suggested. This is what I came up with:

def function (x,n):
    return (n*(x**(n-1)))

assertEqual (function (function (function((function (2, 3))+(function (3, 2)), 4)-function(function (2, 4), 1), 2)+function (function ((function (3,4)),1)-function ((function (6,2))+(function (3,1)),4),3),3), 161027925052617363)

after saving it and running it, the Python shell tells me it's successful, what do you all say?

Once again thanks for all your help!