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37m
revised $\lim_{x\to 0^-} \frac{\pi x\log(x) + \pi x^2}{(x^2-1)^2}$ should not be defined, right?
Fix URL for image
44m
revised Sobolev space $H^2$ norm in terms of gradient
Correct spelling of name
1h
revised The generating function for the Fibonacci numbers
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1h
comment Function problem Show that function $f(x) =\frac{x^2+2x+c}{x^2+4x+3c}$ attains any real value if $0 < c \leq 1$
@coolcheetah If the discriminant is strictly positive, the quadratic polynomial has two distinct real zeros, and then it attains strictly positive as well as strictly negative values. The discriminant being $\leqslant 0$ means the polynomial never changes sign, and the coefficient of the quadratic term tells you whether the values are $\geqslant 0$ or $\leqslant 0$.
2h
revised Showing that: $(\frac{a}{b+c})^2+(\frac{b}{a+c})^2+(\frac{c}{a+b})^2+\frac{10abc}{(a+b)(b+c)(c+a)}\ge 2$
Correct spelling of name
2h
revised Minimize the area of a wire divided into a circle and square.
It's Hermann Amandus Schwarz, not Laurent Schwartz
11h
revised Suppose that $f : U \mapsto \mathbb{R}$ has continuous first partial derivatives.
Correct spelling of name
15h
revised Matrix Norm Inequality
That's the Schwarz without t
20h
revised Prove an inequality.
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21h
revised Can one use Hölder's inequality or some other method for this?
That's the Schwarz without t
21h
revised Can one use Hölder's inequality or some other method for this?
Correct spelling of name
21h
comment Greatest of the numbers given
Differentiate $x^{1/x}$ or, slightly more convenient, $\frac{\log x}{x}$. Note that $2^{1/2} = 4^{1/4}$.
23h
revised Convergence of Integral of Matrices
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1d
revised Find the values of the positive constants $k$ and $c$ such that $-37\le k(3\sin\theta + 4\cos\theta) +c\le 43$ for all values of $\theta$
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1d
revised $D^m\cup_h D^m$, joining $D^m \amalg D^m$ along the boundary $\partial D^m$
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1d
comment Why $ (\cos(\theta) \frac{\partial}{\partial x} + \sin(\theta) \frac{\partial}{\partial y} ) \frac{\partial}{\partial \theta} =0$?
No. But $$\frac{\partial}{\partial\theta}\biggl(\cos \theta \frac{\partial}{\partial x}\biggr) = \frac{\partial \cos \theta}{\partial \theta}\frac{\partial}{\partial x} + \cos \theta \frac{\partial}{\partial\theta}\frac{\partial}{\partial x}$$ and so on.
1d
comment Is Spivak wrong here, or am I just missing something?
You're missing an implicit "for all", ... $x^2 + \alpha xy + y^2 > 0$ for all $x,y\in \mathbb{R}\setminus \{0\}$ ...
1d
revised When does $\|x+y\|=\|x\|+\|y\|?$
Correct spelling of name
1d
revised Convergence of expected values and integrability
It's Hermann Amandus Schwarz, not Laurent Schwartz
1d
revised Largest value of the function $f(x) = \sqrt{x^4-3x^2-6x+13} - \sqrt{x^4-x^2+1}$
Small spelling fixes