Find out a function (fx) so that as x gets closer to 1, value of f(x) gets bigger?

1 Answer
May 13, 2018

Consider #f(x)# as a function of #x-1#.

When #x# gets closer to #1#, #x-1# becomes very small, so its reciprocal becomes very large in absolute value.

We can choose then any strictly increasing function #g(t)# and then let:

#f(x) = g(1/abs(x-1))#

or, to avoid discontinuities:

#f(x) = g(1/(x-1)^2)#

The simplest increasing function is:

#g(t) = t#

in which case we have:

#f(x) =1/(x-1)^2#

but we can also choose for instance:

#f(x) = e^(1/(x-1)^2)#