What is the first term of arithmetic progression if `S_n=3n^2-n` and `d=6` ?
Note that in arithmetic progression, n refers to the number of terms. If we set n=2, the sum of the two terms (`a_1 ` and `a_2` ) is:
`S_n = 3n^2 - n`
`S_n = 3(2)^2-2`
Replacing `S_n` with `a_1` + `a_2` , yields:
`a_1 + a_2 = 10` (Let this be EQ1.)
Also, the d refers to the difference...
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