+0  
 
0
474
1
avatar

What is the domain of the function $$f(t) = \frac{1}{(t-1)^2+(t+1)^2}~?$$ Express your answer in interval notation.

 Nov 9, 2014

Best Answer 

 #1
avatar+130511 
+5

This function will be undefined wherever the denominator = 0

So, setting (r - 1)^2 + (r + 1)^2 = 0  (and expanding)  we have

r^2 - 2r + 1 + r^2 + 2r + 1 = 0

2r^2 + 2 = 0     divide through by 2

r^2 + 1 = 0

And this never = 0

So this is defined everywhere, i.e., ( -∞, ∞ )

 

 Nov 9, 2014
 #1
avatar+130511 
+5
Best Answer

This function will be undefined wherever the denominator = 0

So, setting (r - 1)^2 + (r + 1)^2 = 0  (and expanding)  we have

r^2 - 2r + 1 + r^2 + 2r + 1 = 0

2r^2 + 2 = 0     divide through by 2

r^2 + 1 = 0

And this never = 0

So this is defined everywhere, i.e., ( -∞, ∞ )

 

CPhill Nov 9, 2014

1 Online Users