What is the sum of all real numbers x that are not in the domain of the function

Guest Jul 17, 2017

#2**+2 **

This one is easier than it looks

Any "x" that makes a denominator 0 will not be in the domain

So

x^2 - 7 = 0

x^2 = 7 take both square roots

x = ±√7 but.....notice that the sum of these = 0

x^3 - 8 = 0 the only real number that makes this = 0 is 2

x^4 - 9 = 0

x^4 = 9 take both 4th roots

x = ± ^{4}√9 and, like before, the sum of these two roots = 0

So.....the sum of all the numbers not in the domain is just 2

CPhill
Jul 17, 2017