Question

Grade 11 Math help PLEASE!!

Answer 1

The sum of the first 5 terms in an arithmetic series is 0. The last term is 4. Determine the first term and the common difference.

The answer is supposed to be 4, -1.

Answer 2

I don't know how to find a & d or anything :(

Answer 3

you will have to apply some formula

Sum formula

\[S_n=n/2 (a_1+a_2)\]

Answer 4

*correction
\[S_n=n/2 (a_1+a_n)\]

Answer 5

so what's given?

Answer 6

I have

Answer 7

5 terms, sum of 5 terms = 0 , term 5 = 4

Answer 8

good!

so n=5

\[S_n=0\]

\[a_n=4\]

Answer 9

The formula we use is

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

Answer 10

hmm..

Answer 11

I think you are better off using my formula

\[S_n=n/2 (a_1+a_n)\]

plug in numbers

\[0= 5/2 (a_1 +4)\]
solve for \[a_1\]

Answer 12

I'll try it out , thank you ~=)