Find the sum of the series which is given by, (1) + (2+3) + (4+5+6) + (7+8+9+10) + . . . upto n terms.

Here each expression in the paranthesis needs is to be supposed as a single term of series.

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Type the correct answer in each box. spell all words correctly. a sequence of transformations maps ∆abc onto ∆a″b″c″. the type of transformation that maps ∆abc onto ∆a′b′c′ is a . when ∆a′b′c′ is reflected across the line x = -2 to form ∆a″b″c″, vertex of ∆a″b″c″ will have the same coordinates as b′.