Question

Could anyone offer help on #1 on PS2?
This is what I have so far. Is the index part ok?

def evaluate_poly(poly, x):

##Computes the polynomial function for a given value x. Returns that value.

for index in poly[-1]
return evaluate_poly(poly, x)



##Example:
# f(x) = 7x^4 + 9.3x^3 + 5x^2
# f(-13) = 7(-13)^4 + 9.3(-13)^3 + 5(-13)^2 =180339.9
poly = (0.0, 0.0, 5.0, 9.3, 7.0) # f(x) = 7x^4 + 9.3x^3 + 5x^2
x = -13
print evaluate_poly(poly, x)
##poly: tuple of numbers, length > 0
##x: number
##returns: float

# TO DO ...

Answer 1

If you write poly[-1], then you are only passing it one value to iterate over. For example:
poly = (0.0, 0.0, 5.0, 9.3, 7.0)
In this case poly[-1] => 7.0

You want it to iterate over a range of values. So my hint here is to use the function called xrange. The xrange documentation says this: xrange([start, ] stop [, step])

Answer 2

in case you still need help, i was finally able to complete this by assigning "index" the value of the length of the tuple "poly" -1. len(poly) - 1. this gives the polynomial the correct exponent based on the length of the tuple. you can use a loop to count the indices down while adding them together. no idea if this is the best way to do it, but it works.

Answer 3

just looked at the solution. same results only much less code than mine. LOL