This may be a stupid question thats gonna easily be proved but i just wondered at which step is this wrong. This is taken from a proof in my uni class that limit x->3 (7x) = 21 but just changing one number. why is it wrong and where does it go wrong?
Prove using the definition of a limit that (was originally 21 of course)
|f(x) - L| = |7x - 28| = 7|x - 4|
|x - p| we can control with
If , then
Let be given. Choose , then if =>
From the definition of a limit,
Can somebody point out the mistake in that? surely there must be some step thats wrong!