Mathematics
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OpenStudy (anonymous):
can someone help me evaluate the limit of this equation limit approaches 0(e^(4x) - 1-4x)/(x^2)
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OpenStudy (anonymous):
0
OpenStudy (anonymous):
i get zero over zero
OpenStudy (amistre64):
derive top and bottom seperately; then limit them seperately
OpenStudy (amistre64):
lhopitals rule
OpenStudy (amistre64):
i wonder if you can do that more than once
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OpenStudy (anonymous):
Yes. You can do it as long as both the denominator and numerator have 0/0 or ∞/∞
OpenStudy (amistre64):
2x doesnt seem to help does it lol
OpenStudy (amistre64):
you can? over and over?
OpenStudy (anonymous):
yeah as long as you get 0/0 or infin/infin
OpenStudy (amistre64):
i thought i read that somewhere lol
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OpenStudy (anonymous):
ok so i would get the derivative of the top correct over the derivative of the bottom
OpenStudy (amistre64):
yes
OpenStudy (amistre64):
4.e^4x - 4 2.e^4x - 2
---------- = ---------
2x x
OpenStudy (amistre64):
8.e^4x at 0 = ...8 right?
OpenStudy (anonymous):
yeah thats what the answer sheet got but i still dont understand how you got it
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OpenStudy (amistre64):
x^2; 2x ; 2 tese are the derivatives right? of the bottom
OpenStudy (anonymous):
yeah
OpenStudy (amistre64):
e^4x -1 - 4x; 4.e^4x -4; 16.e^4x for the top
OpenStudy (amistre64):
16.e^4x
------- = 8.e^4x ; at x=0; 8.1 = 8
2
OpenStudy (anonymous):
cant see where you get the 16 from sorry
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OpenStudy (amistre64):
4.e^4x right? derive e^4x again and we get:
4. 4.e^4x = 16.e^4x
OpenStudy (amistre64):
e^u derives to : Du e^u
OpenStudy (anonymous):
ok so u used l hopital twice
OpenStudy (amistre64):
yes lol
OpenStudy (anonymous):
ok ok awesome and we were just talking about that