limit of ((4/x-4/3)/(x-3)) as x approaches 3
i got 4/9 but the answers is -4/9?
why is it negative?|||Because if you use the De L' Ho%26gt;pital rule, you have to find the derivative of 4/x, which is -4/x^2. (You have to use the rule, because the fraction ((4/x-4/3)/(x-3)) becomes a 0/0 when you replace x with 3).|||lt (4/x-4/3)/(x-3)
x-%26gt;3
= lt (4/x-4/3)/(x-3)
x-%26gt;3
= lt (12-4x)/3x(x-3)
x-%26gt;3
= lt 4(3-x)/3x(x-3)
x-%26gt;3
= lt - 4(x-3)/3x(x-3)
x-%26gt;3
= lt - 4/3x
x-%26gt;3
= -4/9
===|||differentiating
-4/x^2/1
allowingthe limit
=-4/9|||lim [ (4/x) - (4/3) ] / (x-3)
= lim [ (4/x) (3/3) - (4/3) (x/x) ] / (x-3)
=lim [ (12/3x) -(4x/3x) / (x-3)
=lim [ (12-4x) / 3x ] / (x-3)
=lim [ (4) (3-x) / 3x ] / (x-3)
=lim [ (4) (-1) / 3x
=lim [ (-4)/ 3x ] = -4/9
x-%26gt;3
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