sequence and series- class 12- solved long questions

Sequence and Series Last part Find the nth term and sum to n terms of given series: a) 1.3+2.4+3.5+…… b) 2+6+12+20+… c) 1.3+3.5+5.7+… d) 1^2+3^2+5^2+… e) 1^2.1+2^2.3+ 3^2.5+… Easy concept Class-12 Mathematics NEB