the answers for the three questions are;
|x|<1/2
|x|<sqrt3
|y|<4
respectively
here are sum examples;
for (1+x)^-1 the set of values for x must be: |x|<1
for (1+2x)^-1 " " " : |x|<1/2
wot i dont understand is the questions that can be split up into partial fractions. Im guessing that u just take the denominator that requires the smallest value of x to be valid and then it applies to the whole function. so that sorts out 1 and 2 but 3 is still causing problems. Sorry i didnt actually number them - but in order - u no wot i mean