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Geometric Progression 



Problem 22 of 23 


22. Find , where a = , b = and n = .










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Geometric Progression 
22. Find `1^2 + 2^2 + ...+ 10^2` , ( Find `a^2 + b^2 + ... + n^2` , where a = 1 , b = 2 and n = 10 . )
Here Find ` 1^2 + 2^2 + 3^2 + ... + 10^2 `
`= sum i^2` (where `i = 1,...,10`)
`= (n (n + 1)(2n + 1)) / 6` (where `n = 10`)
`= (10 (10 + 1) (2×10 + 1)) / 6 `
`= (10 × 11 × 21) / 6`
`= 5 × 11 × 7`
`= 385`







