# not sure about a few formulas?

• Jan 27th 2008, 08:26 PM
simplekin
not sure about a few formulas?
Hello, here are a few formulas that will be given to us during an upcoming exam, and i dont know what each one does.

Tn = a + (n -1)d

Sn = n/2[2a + (n-1) d]

Sn = n/2(a +tn)
• Jan 27th 2008, 08:44 PM
mr fantastic
Quote:

Originally Posted by simplekin
Hello, here are a few formulas that will be given to us during an upcoming exam, and i dont know what each one does.

Tn = a + (n -1)d Mr F says: nth term of an arithmetic series whose first term is a and whose common difference is d.

Sn = n/2[2a + (n-1) d] Mr F says: Sum of the first n terms of an arithmetic series whose first term is a and whose common difference is d.

Sn = n/2(a +tn) Mr F says: Sum of the first n terms of an arithmetic series whose first term is a and whose nth term is tn.

Have you actually studied the material that these formulae relate to? Seriously.
• Jan 27th 2008, 08:48 PM
simplekin
Quote:

Originally Posted by mr fantastic
Have you actually studied the material that these formulae relate to? Seriously.

yes, i have in fact, but due to very shady memory, i forgot it, just need to get it set back in place.
• Jan 27th 2008, 08:56 PM
mr fantastic
Quote:

Originally Posted by simplekin
yes, i have in fact, but due to very shady memory, i forgot it, [snip]

That's why God invented class notes and textbooks.