Calculus I - Question about derivatives and corners...

[Guest]

Does anyone know how to do this problem....

let f(x) = ll2x-7l - lx+4l. The grapg of f has corners when x is equal to A, B, C, and D. Assume A<B<C<D. Then

A =
B =
C =
D =

 

[Unco]

f(x) = ||2x - 7| - |x + 4||

Split the domain into intervals where |2x - 7| = 2x - 7 or -(2x - 7), same for |x + 4|, and then consider what f(x) looks like on those intervals, and hence how the outermost absolute value signs further split up the domain.