Always, Sometimes, Never Question

Question

When is this statement not true:

If $a<2b$, then $a<4b^2$

I have it on good authority that this statement is sometimes true. I can come up with values easily that make it true but cannot come up with values that would make it not true. Any suggestions would be greatly appreciated.

Answer 1

Try a = 1/2 and b = 1/3 that should work

Answer 2

Take $a=b=0.1$, and it should do what you want.