I only got this far with the answer. I don't understand how recursive functions work. I would really appreciate any help. And also, if someone could explain what base and recursive calls are, that'd be great.
def multi(n):
if n==1:
return 4
Recursive function is a function that makes a call to it self. for example:
def multi(n):
if n>0:
return n * multi(n-1)
else:
return 0
To prevent infinit recursion you have to define a case where the function does not make a call to it self.(in our example it's in else statement when n==1).
Please try this code :
def multi(n):
return (5 + multi(n-1)) if n>0 else 0;
this function is a 5n, here's the explanation:
when n = 1 the call is like this :
output : 5 + multi(0) --> multi(0) = 0, so 5 + 0 = 5
It's something like this :
multi(3)
|
-- 5 + multi(2)
|
--- 5 + (5 + multi(1))
|
---- 5 + (5 + (5 + multi(0)))
|
----- 5 + 5 + 5 + 0
5n --> if n = 3 --> 5(3) = 15
output multi(3) = 15, as same as 5(3)=15.
5(3) = 5+5+5 = 15
5(2) = 5+5 = 10
in recursion, you'll do it like this:
5(0) = 0
5(1) = 5 + 0 = 5
5(2) = 5 + 5 + 0 = 10
...
5(n) = 5 + f(n-1), where f(0) = 0, so n must greater than 0. To prevent infinite loop.
Case for 5(3) :
1. 5(3) = 5 + f(2)
2. f(2) = 5 + f(1)
3. f(1) = 5 + f(0)
4. f(0) = 0
So, you will get 5(3) = 5 + (5 + (5 + 0)) = 15
Hope this help you to understand it :D
