Time management is very much important in IIT JAM. The eduncle test series for IIT JAM Mathematical Statistics helped me a lot in this portion. I am very thankful to the test series I bought from eduncle.
Nilanjan Bhowmick AIR 3, CSIR NET (Earth Science)
Jagat Chaudhary
Thankyou for asking Jagat Chaudhary Eduncle expert (MA) IIT Bhubaneswar
but answer on my book is
i know because your question has a misprint. there should be a plus sign after (1+y)^2, then you will get the result as your book. I hope you get it.