having trouble writing a recursive algorithm for 2^n

i am writing a recursive algorithm for the function 2^n, and the formula that must be used is: 2^(n-1) + 2^(n-1) = 2^n
heres what i have so far:

Code:

---

//computes 2^n recursively using the formula 2^n=2^n-1 + 2^n-1
x(int n)
{
    if(n=0)
          return 1;
    else
}

---

i am not sure how to do the recursion to get that formula, can someone point me in the right direction? thanks

Do you understand the concept of recursion? Your statement should include at least one call to the x() function.

Quote:

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Originally Posted by kevinskrazyklub

i am writing a recursive algorithm for the function 2^n, and the formula that must be used is: 2^(n-1) + 2^(n-1) = 2^n
heres what i have so far:

Code:

---

//computes 2^n recursively using the formula 2^n=2^n-1 + 2^n-1
x(int n)
{
    if(n=0)
          return 1;
    else
}

---

i am not sure how to do the recursion to get that formula, can someone point me in the right direction? thanks

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Just think about it algebraically:

2^n = 2^(n-1) + 2^(n-1) = 2 * 2^(n-1)
x(n) = 2^n
x(n) = 2 * x(n-1)

Make sense? I haven't written any code and I still feel like I'm giving away the answer.

Quote:

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Originally Posted by Hermit

Just think about it algebraically:

2^n = 2^(n-1) + 2^(n-1) = 2 * 2^(n-1)
x(n) = 2^n
x(n) = 2 * x(n-1)

Make sense? I haven't written any code and I still feel like I'm giving away the answer.

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makes perfect sense thanks.