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OpenStudy (anonymous):
Find the indefinite integral. (Remember to use ln |u| where appropriate.)
(x^3 − 3x^2 + 5x − 12)/(x^2 + 4) dx
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OpenStudy (anonymous):
its an indefinite integral but im lost on how to even solve it
myininaya (myininaya):
have you divided?
myininaya (myininaya):
x-3
-----------------------------
x^2+4 | x^3 -3x^2 +5x -12
-(x^3 +4x)
-----------------------
-3x^2+x-12
-(-3x^2 -12)
--------------
x
myininaya (myininaya):
so i got
\[\frac{x^3-3x^2+5x-12}{x^2+4}=x-3+\frac{x}{x^2+4}\]
if i did my arithmetic right above
OpenStudy (anonymous):
yup yup good arithmetic
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OpenStudy (zarkon):
you did :)
myininaya (myininaya):
\[\int\limits_{}^{}(x-3+\frac{x}{x^2+4})dx\]
myininaya (myininaya):
we can use substitution for the 3rd integral
\[\int\limits_{}^{}x dx+\int\limits_{}^{}-3 dx+\int\limits_{}^{}\frac{x}{x^2+4} dx\]
myininaya (myininaya):
lol
myininaya (myininaya):
\[\frac{x^2}{2}-3x+\int\limits\limits_{}^{}\frac{x}{x^2+4}dx \]
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myininaya (myininaya):
\[u=x^2+4 => du=2x dx =>\frac{1}{2} du=x dx\]
\[\frac{x^2}{2}-3x+\frac{1}{2}\int\limits_{}^{} \frac{du}{u}+C=\frac{x^2}{2}-3x+\frac{1}{2}\ln|u|+C\]
myininaya (myininaya):
\[\frac{x^2}{2}-3x+\frac{1}{2}\ln(x^2+4)+C \]
OpenStudy (zarkon):
I like that you dropped the absolute value since you didn't need it in the end :)
myininaya (myininaya):
:)
right because x^2+4>0
OpenStudy (anonymous):
so whats the final answer?
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OpenStudy (zarkon):
:O
myininaya (myininaya):
i'm puzzled
myininaya (myininaya):
did you not follow anything i did?
OpenStudy (anonymous):
lol
OpenStudy (zarkon):
I would guess no :)
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OpenStudy (anonymous):
I need answer now!
OpenStudy (anonymous):
MIA....
OpenStudy (anonymous):
ugh my comp keeps freezing sorry
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