consider the arithmetic sequence is 7,12,17 a) what is the common difference b) what is difference between the sum of first 20 te

1 thought on “consider the arithmetic sequence is 7,12,17 a) what is the common difference b) what is difference between the sum of first 20 te”

1. a) D= a_2-a_1

   =12-7= 5

   Common difference= 5

   b)

   [tex] \tt \: = \frac{ 20 }{ 2 } (2(7)+(40-1)(5)) \\ \tt \: 10\left(2\times 7+\left(40-1\right)\times 5\right) \\ \tt \: 10\left(14+\left(40-1\right)\times 5\right)\\ \tt \:10\left(14+39\times 5\right)\\ \tt \: 10\left(14+195\right)\\ \tt \: 10\times 209 \\ \tt \:2090 ——–i) \\ \\ \tt \:= \frac{ 20 }{ 2 } (2(7)+(20-1)(5))\\ \tt \:10\left(2\times 7+\left(20-1\right)\times 5\right)\\ \tt \: 10\left(14+\left(20-1\right)\times 5\right) \\ \tt \:10\left(14+\left(20-1\right)\times 5\right)\\ \tt \: 10\left(14+19\times 5\right)\\ \tt \: 10\left(14+95\right)\\ \tt \: 10\times 109 \\ \tt \:1090——-ii)[/tex]

   From Eq i) and ii)

   2090-1090=1000

   Difference between the sum of first 20 term and the sum of next 20 term= 1000

   [tex] \sf \: @WildCat7083[/tex]

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