Doubt in the complexity analysis of an algorithm

Question

I need to know how to compute the complexity of this algorithm using the recurrence equation.

public int qdr(int x, int n) {
   if(n == 0)
     return 1;
   else
     return x * qdr(x, n-1);
}

It is a recursive algorithm that reads two numbers x and n and returns the result of x n

Answer 1

and very simple :)

when n > 1, the function makes an operation that has constant time, multiplication, and makes a recursive call that has size n - 1.

so the recurrence is:

T(n) = T(n-1) + 1 (ou O(1), da na mesma)
T(1) = 1

if you solve you will arrive at a sum of type 1 + 1 + 1+ ... + 1, with n a. that of n. therefore, the function is linear, O(n).