The Total solution for NCERT class 6-12
1.2.5 + 2.3.6 + 3.4.7 + ……..
Let Tn bethe nth term of the given series.We have:
Tn = n(n + 1) (n + 4)
= n (n2 +5n + 4)
= n3 +5n2 + 4n
Now, let Sn bethe sum of n terms of the given series.We have: