21+22+23+24+…..+200=….
Jawaban:
19.890
Penjelasan dengan langkah-langkah:
21 + 22 + 23 + 24 + …. + 200 =
200 – 20 = 180
a = 21 b = 1
U180 = 21 + 179 . 1
= 200 . 1 = 200
Sn = n/2 ( 2a ( n – 1 ) b )
S180 = 180/2 ( 2.21 ( 180 – 1 ) 1 )
= 90 ( 42 + 179 )
= 90 × 221
= 19.890