This question was asked in Ex 13.2, 4

Sir can you please tell me that in chapter surface areas and volumes exercise no.13.2 . Question no.4 how did you take area of 1 revolution=area of roller....i have not understood only this single line...can you please tell my answer

Albert Einstien

July 14, 2018, 10:07 p.m.

Answer the question...