What is the output of this?

[shroom]

 

[shroom]

Is it 363 or 364?

 

[JavaJames]

364

 

[cbreemer]

Without getting your calculator, ask yourself if it can be 364. For x=3 all terms are odd, so for n=5 you have a sum of 5 odd numbers. Surely that cannot be even.

 

[BlackCube]

This series can be rearranged into a simple expression.
(x^(n+1) - 1) / (x - 1)

 

[cbreemer]

This series can be rearranged into a simple expression.
(x^(n+1) - 1) / (x - 1)

True. But the assignment was to compute a sum. And the question was about the value of the output.

 

[BlackCube]

Yes cbreemer.
I would code the sum, and use the expression to test the output, for more than one case.

 

[cbreemer]

Yes cbreemer.
I would code the sum, and use the expression to test the output, for more than one case.

Ok ! Never hurts to have an alternative method to check things.

 

[JavaJames]

Without getting your calculator, ask yourself if it can be 364. For x=3 all terms are odd, so for n=5 you have a sum of 5 odd numbers. Surely that cannot be even.

It’s 1+ (the sum of 5 odd numbers) - so that has to be even.

 

[cbreemer]

It’s 1+ (the sum of 5 odd numbers) - so that has to be even.

Ah yes of course. I forgot to count the zero power 🙄 The reasoning stands though - there should be no doubt between 363 or 364.