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Aug
11
answered A Residue problem
Aug
11
answered Differential Equation - how to solve for the equation of a curve passing through points?
Aug
10
comment Lagrange Multiplier Method: Why is the Langragian function defined as $f(x,y)+\lambda \cdot g(x,y)$?
The Lagrangian $L:=f-\lambda g$ is a purely formal device without any intuitive geometrical or physical content. The essential point is the following: In a conditionally stationary point $x$ we necessarily have $\nabla f(x)=\lambda\nabla g(x)$ for some $\lambda\in{\mathbb R}$, whereby this latter equation can be "explained intuitively".
Aug
10
revised A Tough Problem about Residue
added 70 characters in body
Aug
10
answered A Tough Problem about Residue
Aug
10
comment “Mean value like” problem.
@Aretino: No. The derivative satisfies the IVT without the assumption of being continuous. (This implies that a discontinuous $f'$ has to be very discontinuous.)
Aug
10
comment May be a trivial question regarding constrained optimization
Please give explicitly the objective function, the constraint, and the domain of allowed $x$.
Aug
10
comment Proving that the tangent vector of a simple closed curve rotates by $ 2 \pi$
It is unclear how the essential assumption that $\gamma$ is simple has been used.
Aug
10
revised If $f(\alpha x, \alpha y) = f(x,y)$ is $f$ some special function?
added 38 characters in body
Aug
9
answered If $f(\alpha x, \alpha y) = f(x,y)$ is $f$ some special function?
Aug
9
comment How to calculate matrix exponential of a $2\times 2$ matrix with repeated e values
@Bernard: Thank you. After JMoravitz's answer I refrain from updating mine.
Aug
9
revised How to calculate matrix exponential of a $2\times 2$ matrix with repeated e values
added 98 characters in body
Aug
9
answered How to calculate matrix exponential of a $2\times 2$ matrix with repeated e values
Aug
9
answered How do i convince students in high school for which this equation: $2^x=4x$ have only one solution in integers that is $x=4$?
Aug
9
comment Digit Code Combination Problem
Concerning the protocol: Are codes assigned in the order the new employees show up, or does the person assigning the codes see all $2r$ new proposals before assigning any codes that day?
Aug
9
answered “Mean value like” problem.
Aug
9
revised finding an operation for a semicircle
added 151 characters in body
Aug
9
answered finding an operation for a semicircle
Aug
9
revised The triangle must be obtuse if two of its medians are perpendicular?
deleted 1 character in body
Aug
8
revised The triangle must be obtuse if two of its medians are perpendicular?
edited body