2007-01-28 23:21:04 · 9 answers · asked by Vinson j 1 in Science & Mathematics ➔ Mathematics
S10=10/2[2(-10)+(10-1)8]
=5(-20+72)
=260
2007-01-28 23:26:44 · answer #1 · answered by Maths Rocks 4 · 0⤊ 0⤋
First term a = -10
Common difference d = -2 - -10 =8
number of terms n = 10
Sum of first 10 terms = n / 2 ( 2a + (n-1)d)
= 10/2 (2*-10 +(10-1) 8)
=260 Ans.
2007-01-28 23:34:03 · answer #2 · answered by ATS 2 · 0⤊ 0⤋
260
2007-01-28 23:25:25 · answer #3 · answered by MC 3 · 0⤊ 0⤋
be conscious that the sum to the nth term is a million + [2+3] + ... + [(T_{n-a million}+a million) + ... + T_n] = a million + 2 + ... + T_n, the place T_n denote the nth triangular selection. all of us understand that T_n = n(n+a million)/2, so we are able to apply the prevalent arithmetic series formulation to compute the sum: a million + 2 + ... + T_n = (a million/2) [a million + n(n+a million)/2] * n(n+a million)/2 = (a million/8) (n^4 + 2n^3 + 3n^2 + 2n). nonetheless, notice that the sum is the {T_n}th triangular selection, which back proves that a million + 2 + ... + T_n = T_{T_n} = [n(n+a million)/2] ([n(n+a million)/2] + a million) / 2
2016-12-13 03:29:16 · answer #4 · answered by declue 4 · 0⤊ 0⤋
a=-10
d=8
S10=10/2(2*-10+9*8)
sum=260
2007-01-29 00:03:59 · answer #5 · answered by Anonymous · 0⤊ 0⤋
Hmm..Arithmetic progression.
The difference is 8.
Total sum=(n)(n-1)(d)(0.5)+(n)(-10)
=(10)(9)(0.5)(8) + (10 x-10)
=260
2007-01-28 23:32:53 · answer #6 · answered by A 150 Days Of Flood 4 · 0⤊ 0⤋
260
-10,-2,6,14,22,30,38,46,54,62
-10+-2+6+14+22+30+38+46+54+62
-12+20+52+84+116
8+136+116
144+116
260
2007-01-29 00:58:36 · answer #7 · answered by rubydragon 2 · 0⤊ 0⤋
260.
2007-01-28 23:50:59 · answer #8 · answered by malo! 2 · 0⤊ 1⤋
arithmetic progression
common difference=d=-8
Sum of ten terms=10(-10)+9.8.(-8)/2
=-100-72.4
=-100-288
=-388
2007-01-28 23:32:50 · answer #9 · answered by iyiogrenci 6 · 0⤊ 1⤋