+0

# Hard Question that I need help with!

0
40
3

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

Guest Jul 17, 2017
Sort:

#1
+86
0

MIRB15  Jul 17, 2017
#2
+75017
+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
#3
+4060
+1

HMMMMM I see what you did there......   👀

hectictar  Jul 17, 2017

### 9 Online Users

We use cookies to personalise content and ads, to provide social media features and to analyse our traffic. We also share information about your use of our site with our social media, advertising and analytics partners.  See details