Aditya Gupta
Last Activity: 5 Years ago
here area refers to geometric area, which is always positive as opposed to algebraic area.
note that when f(x) is positive, ∫|f(x)|dx from m to n= ∫f(x)dx from m to n represents the area bound by f(x), x axis and lines x= m and x= n.
when f(x) is negative (|f(x)|= – f(x)), ∫|f(x)|dx from m to n represents the area bound by |f(x)|, x axis and lines x= m and x= n. however, this area is also the geometric area bound by f(x), x axis and lines x= m and x= n, since area= |∫|f(x)|dx from m to n|= |– ∫f(x)dx from m to n|= |∫f(x)dx from m to n|
hence, ∫|f(x)|dx from a to b always represents the geometric (positive) area b/w f(x), x axis and the lines x= a and x= b.