Thanks very much. I did a question like that on a test but I used a triple integral because I thought we slways had to use triple integrals for 3D shapes...
Integration by u substitution, if u = a^2 - r^2 then du = -2r dr . In the integral we want to solve we have r dr and we want to replace it with du but du = -2r dr. Need to solve for r dr - divide both sides by negative 2 -> r dr = -1/2 du
Super helpful video! Thank you!
Thanks very much. I did a question like that on a test but I used a triple integral because I thought we slways had to use triple integrals for 3D shapes...
appreciate the help!!
Thanks!
03:49
Please explain how r dr = -½ du
Integration by u substitution, if u = a^2 - r^2 then du = -2r dr . In the integral we want to solve we have r dr and we want to replace it with du but du = -2r dr. Need to solve for r dr - divide both sides by negative 2 -> r dr = -1/2 du
@@justinphillips6900 Ay thanks man! Appreciate it