1] l x + y l < or equal to l x l + l y l
x^2 + 2xy + y^2
The Attempt at a Solution
Left side. i Squared left side to begin with, and i got x^2 + 2xy + y^2 and also did the same for the right side, but it would have absolute sign between each variable.
x^2 + 2xy + y^2 < or equal to lxl^2 + 2lxllyl + lyl^2
so its just (x + y)^2 < or equal to ( lxl+lyl )^2
not sure what im supppose to do next..
it just seems like im doing somethign and undoing something without any purpose.
can anyone clear this from my head?