Joseph Myers
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 Dec29 awarded Autobiographer Dec16 awarded Caucus May23 comment Using Integration By Parts results in 0 = 1 There is no mistake, and it does not prove 0 = 1. It proves only that 0 = 1 + $C$ for some constant $C$. An indefinite integral always has a constant of integration to be taken into account. You may have noticed in Calculus 2 that you come up with the exact same kind of result when you integrate by parts the expression $\ln (x+1)$ directly without intermediate $u$-substition vs. doing it with intermediate $u$-substition, as another example. May1 answered Linear Algebra Confusion! Mar20 awarded Yearling Dec5 comment Solving Partial differential equation , distinguishing the meaning of boundary condition and Initial condition. Yes, boundary basically is like the external state which can be measured without entering the object being considered. In a way, the "future" is like the internal state of the object which we cannot penetrate. So the initial condition when time is 0 (the present time), is like the boundary of the object that represents the future. So initial conditions are very closely related to boundary conditions. The initial condition when time equals zero is simply the boundary condition at the edge of the object that represents the future. Dec4 answered Solving Partial differential equation , distinguishing the meaning of boundary condition and Initial condition. May14 awarded Caucus May10 answered Is mathematics one big tautology? May3 awarded Supporter Apr30 comment Truth Value of Multiple Quantifiers @user794954 your first statement is false as I said, and your example shows why it is wrong. Your second statement is true and is not equivalent to the first. Apr29 answered Truth Value of Multiple Quantifiers Apr26 answered Logarithm rules, which one has priority? $\ln2e^{2x}$ Apr4 comment Studying for the Putnam Exam You may do that if you like. I did not know there were official solutions now available online. Apr3 awarded Teacher Apr3 comment Studying for the Putnam Exam I totally agree that the proof writing classes and the resulting understanding of making a logical argument starting from premises while defining every item along the way, is more valuable than just knowing how to do calculus!! Apr3 answered Studying for the Putnam Exam