Thread: Please help me solve

List the values at which the function



Is not defined.

This question does not have an answer in my text book so I cannot deduce where I have gone wrong, though actually I haven't gotten anywhere...just staring at it and repeating it to myself. I've tried factorising it out, but that doesn't work see (x+3)(x-3)..... must be a positive number right?

well you did the right thing in factorising the bottom line. The function is not defined if the denominator is 0

=> f(x) not defined at

=> not defined and

Originally Posted by Tekken

well you did the right thing in factorising the bottom line. The function is not defined if the denominator is 0

=> f(x) not defined at

=> not defined and

which is clearly defined.


. Note that and hence over the real numbers.

This means there are no real values of x for which f(x) is undefined.


There are complex ones though: and it's conjugate . This comes from solving over the complex numbers.


Rewrite f(x) in terms of i (where )



The difference of two squares can now be used

Ah so a trick question. I always fall for these. I am so mathematically challenged

Thank you for your help