Question

I need help finding the equation for the sum with 5+7+9+11+13=∑g(k) of n=0 to 4. All I can get is k+2 but apparently this is not the correct answer.

Answer 1

As a side note, make sure your variables are constant (unless your teacher gave them to you that way); we shouldn't have both n and k in this summation. I will only use n.

So this is asking for a function that gives you the numbers 5, 7, 9, 11 etc... in a summation notation. If we are going from n=0 to n=4, we will have 5 results that we add together (n=0, n=1, n=2, etc...).

What gives us 5 when n=0? We need an n in our equation.
Let's try some stuff out. You got n+2. Okay. When n=0, we get 2. That doesn't equal 5 obviously, which should be our first term.

Let us try something else, something that gives us 5 but still has n=0. What if we put a 0 on the thing we add by and kept 5 as a constant?
5+2n. Cha-ching! Now we have something that gives us our sum.

\[\sum_{n=0}^{4}5+2n\]

Answer 2

Ok, I understand now. I was trying to figure out with n=1, so it confused me when n was equal to 0. Thanks!!