Find the sum of the first 62 terms of the arithmetic sequence

35,34, 33, 32........

Question

Find the sum of the first 62 terms of the arithmetic sequence

35,34, 33, 32........

campbell_st · Answer

ok the sum of an arithmetic sequence can be found using the formula 

$$S_{n} = \frac{n}{2}[2a + (n - 1)d]$$

where n = number of terms
          a = 1st term 
          d = common difference

in your question you have   n = 62
                                         a = 35
                                         d = -1
just substitute into the formula and evaluate

anonymous · Answer

I can't figure it out still.....

anonymous · Answer

like i did what you say but i got something that wasn't right

campbell_st · Answer

ok here it is 

$$S_{62} = \frac{62}{2}[ 2 \times 35 + (61 - 1) \times (-1)]$$

doing it in bits you get

$$S_{62} = 31[70 + 61 \times (-1)]$$

this may help

campbell_st · Answer

what answer did you get... ?