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Arithmetic Progression 



Problem 5 of 19 


5. For arithemetic progression f( ) = , then find S( ).










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Arithmetic Progression 
5. For arithemetic progression f( 17 ) = 6 , then find S( 33 ).
We have given `f(17) = 6` and we have to find `S_33 = ?`
We know that, `f(n) = a + (n  1)d`
`f(17) = a + (17  1)d`
`=> a + 16d = 6 >(1)`
We know that, `S_n = n/2 [2a + (n  1)d]`
`S_33 = 33/2 * [2a + (33  1)d]`
`=> S_33 = 33 * [a + 16 d]`
`=> S_33 = 33 * 6` (Using (1))
`=> S_33 = 198`





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