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Is there a number a such that the limitlimx32x23ax+xa1x22x3exists?

 Sep 12, 2019

Best Answer 

 #2
avatar+9490 
+1

We want to find  a  such that the numerator is also zero when  x = 3

 

That is, we want to find  a  such that...

 

2(3)2 - 3a(3) + 3 - a - 1  =  0

 

18 - 9a + 3 - a - 1  =  0

 

20 - 10a  =  0

 

20  =  10a

 

2  =  a

 

So yes, when  a = 2,  the limit exists.

 

Check:

 

limx32x26x+x3x22x3 = limx32x(x3)+1(x3)(x3)(x+1) = limx32x+1x+1 =74

 Sep 12, 2019
 #1
avatar
-1

 

It's obvious that, no matter what the value of "a" is, when x=3 the denominator becomes zero. 

 Sep 12, 2019
 #2
avatar+9490 
+1
Best Answer

We want to find  a  such that the numerator is also zero when  x = 3

 

That is, we want to find  a  such that...

 

2(3)2 - 3a(3) + 3 - a - 1  =  0

 

18 - 9a + 3 - a - 1  =  0

 

20 - 10a  =  0

 

20  =  10a

 

2  =  a

 

So yes, when  a = 2,  the limit exists.

 

Check:

 

limx32x26x+x3x22x3 = limx32x(x3)+1(x3)(x3)(x+1) = limx32x+1x+1 =74

hectictar Sep 12, 2019

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