Mathematics
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OpenStudy (wade123):
@perl
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OpenStudy (wade123):
@perl help plz!!
OpenStudy (perl):
can you show me any work you did so far
OpenStudy (wade123):
so i can distribute first right?
OpenStudy (wade123):
i havnt dtarted this problem because im confused
OpenStudy (perl):
start with a u substitution
u = x^3 - 4
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OpenStudy (wade123):
ohh ok i know how to do this problem, one second while i colve it out, will you check it for me after?
OpenStudy (perl):
ok
OpenStudy (wade123):
@perl i got 1/4(x^3-4)^4+C , could you please check? @perl
OpenStudy (wade123):
i think i did it correctly, im trying to upload my work because i did it on a piece of paper
OpenStudy (solomonzelman):
when you do your u-sub you have another 1/3 overthere. Incorrect.
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OpenStudy (solomonzelman):
u=x^3-4
du=3x^2 dx ---> (1/3) du = x^2 dx
OpenStudy (solomonzelman):
So
Integral of x^2 (x^3-4) dx
the x^3-4 gets replaced by u
the x^2 dx get replaced by (1/3) du
you have (1/3) Integral u^4 du
OpenStudy (solomonzelman):
and when you integrate, you divide by 1/4 yes, but you ALREADY have the 1/3 there, so in the final answer you have a coefficient of 1/12 (not 1/4).
OpenStudy (solomonzelman):
Is this making any sense /
OpenStudy (solomonzelman):
??
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OpenStudy (wade123):
ohh so my final answer would be 1/12(x^3-4)^4+C? @perl
OpenStudy (wade123):
* @SolomonZelman
OpenStudy (solomonzelman):
yes, and do you fully understand why ?
OpenStudy (wade123):
yes!
OpenStudy (solomonzelman):
very nice... have a good night, I am going offline:)
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OpenStudy (wade123):
@perl
OpenStudy (wade123):
@perl ????