1.4+2.5+3.6+….n(n+3)=
n(n+1)(n+5)/3
n(n+1)(n+2)/3
n(4n2+6n-1)/3
n(n+1)(n+2)
1.22+2.32+3.4+….+n(n+1)2=
n(n+1)(n+2)(3n+5)/12
n(n+1)(n+2)(n+3)/4
2n(n+1)(n+2)(n+3)
n(n+1)(n+2)(3n+1)/12
A= 20th term of 1.2+2.3+3.4+…. B=15th term of 1.3+3.5+5.7+… C=10th term of 1.22+2.32+3.42+… D=10th term of 2.12+3.22+4.32+…. Then the increasing order of A, B, C, D is
A, B, C, D
A, C, D, B
A, B, D, C
A,D, B, C