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)
Priyanka kumari
when vectors are antiparallel , then angle between them is 180°. Cos180°= -1. kindly see the attached file for more detail....