Sequence. (1 Viewer)

[RealiseNothing]

Ah yes of course, oops :/
Then yeah it would work out to your answer

I got:



Whilst if you simplify yours you get:



So I'm not sure which is right, the only difference is that half out the front of the T in the denominator. Might try some substitutions see which works.

 

[Carrotsticks]

 

[RealiseNothing]

That's exactly what I got isn't it? Just expressed in a different form.

 

[Carrotsticks]

Yep, I didn't take a look at previous posts and just did my own thing.

 

[Sy123]

Yep, I didn't take a look at previous posts and just did my own thing.

Hmm, if this is the case then why is my answer wrong? (taking into account Realise's correction of my solution)

 

[Carrotsticks]

Hmm, if this is the case then why is my answer wrong? (taking into account Realise's correction of my solution)

Your method isn't wrong, you just made a typo, which prevented you from getting the right answer.

Wait a moment, adding solution to this post.

 

[Sy123]

My solution



The coefficient in front of T for the denominator turns out double Realise's ?

 

[Carrotsticks]

My solution

View attachment 26535

The coefficient in front of T for the denominator turns out double Realise's ?

The error is in the 4'th line, when you have the arrow -->

You shifted the subscript down by 1 for the S_n terms, but you forgot to do it for the n term.

 

[Sy123]

The error is in the 4'th line, when you have the arrow -->

You shifted the subscript down by 1 for the S_n terms, but you forgot to do it for the n term.

But isnt it true that we can:



Which is then S_n=S_(n-1)+n?
I dont get what you mean by shifting the subscript down for the n-term

 

[Carrotsticks]

After your line...



You had:



This is correct. But then you shifted down the subscript so n+1 --> n and n --> n-1.

So you should have gotten:



But instead, you just had:

 

[Sy123]

After your line...



You had:



This is correct. But then you shifted down the subscript so n+1 --> n and n --> n-1.

So you should have gotten:



But instead, you just had:

OH, I see that ok thank you. I feel so noob compared to others lol