How do you prove (a + b)^2 = a^2 +2ab + b^2

hint: (a + b)2 = (a + b)(a + b) may be a good way to get started. you can then do more algebra steps to the (a + b)(a + b) expression to eventually re-write it as a2 + 2ab + b2 .

why not give a simple counter example? if a=[0010] and b=[0001], then (a+b)2=[0011]2=[0011], – nex sep 3 '16 at 19: 30

but a2+2ab+b2=[0010]2+2[0010][0001]+[0001]2=[]+2[0010]+[0001]=[0021]

hello from mrbilldoesmath!

answer:

the domain is the set { -2, 0, 2, 3}

discussion:

the domain is the set of x values in the ordered pairs (x,y). taking the x, or first component, of each ordered pair gives   -2, 0, 2, 3.

you,

mrb