KCET2017MathematicsBinomial Theorem
( 3+5+7+ ) to ( n ) terms is
Options
- A( n(n+2) )
- B( (n-2) )
- C( n² )
- D( (n+1)² )
Correct answer
A. ( n(n+2) )
Step-by-step solution
Given that, ( 3+5+7+ . n ) terms It is in A.P. with first term, ( a=3 ) and common difference, ( d=2 ). So, sum of first ( n ) terms of A.P. series is given by [ array l S_ n = n 2 [2 a+(n-1) d] = n 2 [2(3)+(n-1) 2] =n(n+2) array ]