fossil narwhal
Hey I'm doing integration by parts and I feel like I'm constantly missing something in the method. In this example, u is assigned as x^2, it's derivative is found, and then that equation is solved for dx, to be plugged back into the original. When it's substituted back, it's done as 1/2 and the 1/x is missing.
modern ingotBOT
compact karma
this is substitution not by parts
plug dx = 1/2x du into the integral yourself and see what happens
fossil narwhal
this is substitution not by parts
My bad! I'm wrestling with both right now and got them mixed up hah
fossil narwhal
plug dx = 1/2x du into the integral yourself and see what happens
Oh you're so right, the x in the denominator cancels with the x that multiples that e term
compact karma
indeed it does
fossil narwhal
This is the second time these disappearing terms have come up and I was thinking that there was some magic cancelling with the dx and x
Thanks for your help, that clears everything up
compact karma
ya one general use c ase of u-sub is to make these things "disappear" to make the integral easier
fossil narwhal
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modern ingotBOT
Solved