+0  
 
0
30
1
avatar+1348 

Find the smallest integer value of $c$ such that the function $f(x)=\frac{2x^2+x+5}{x^2+4x+c+12x+x^2}$ has a domain of all real numbers.

 Jan 20, 2024
 #1
avatar+129895 
+1

Simplify the denominator to

2x^2 + 16x + c

 

We need  the discriminant of  this  to be < 0     (so  that the denominator has no real 0's )

 

16^2   - 4(2)c  <   0

256 - 8c <  0

256 < 8c

32 < c

 

33 is the  smallest integer

 

cool cool cool

 Jan 20, 2024

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