Find V(x- x^2, [-1,2]) and V(cos(4(pie)x),[0,1]).

V(x- x^2, [-1,2])= V(x- x^2, [-1,0])+V(x- x^2, [0,1])+V(x- x^2, [1,2])=

0+0+2=2

V(cos(4(pie)x),[0,1])= 1+1=2

I was a little confused about finding the variation of a monotone function but can anyone please tell me if I found the total variations for both functions or did i go wrong at some point?