Find the sum of the series 1.2.3.4.5 + 2.3.4.5.6 + …… n terms.

first find nth term of given series

then apply summation

u will get

 

 

but this methd is more cmplicated for this type of problems.

so to save time use verificaion process that is u have put a natural number in place of n 

if u took n=1 then add first term of given series

if u took n=2 then add first two terms of given series mstly n=1 gives u crrect ans

What is verification process?? plzz explain this question hw to solve this with procedure

i mean to say that certain options r provided to u in competitive exams

in the above problem may be 4 options  will be provided to u

definetly those options will be in terms of n

so, now u have to put n=1 in those options u will get certain answer and it will be equal to 1.2.3.4.5 as it is the first term in given series

if more than one option satisfies it,then take n=2 and it will be equal to 1.2.3.4.5+2.3.4.5.6. (it is the sum of first two terms in given series)

 

REMEMBER U MUST TAKE NATURAL NUMBERS IN THE PLACE OF n 

it is best way to solve this kind of problems.i always use this method  nd always get correct ans

for simple series u can easily apply summation method

 

hope it will also helped u 

And approve if it helped u