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Feb
21
comment What happends when you multiply a constant or variable by a trig function?
well, what happens when you multiply a constant or variable by 1, a number less than 1 but greater than 0, 0, a number less than 0 but greater than -1, and -1? Now imagine doing that periodically.
Feb
21
comment How does this proof of the Cauchy-Schwarz Inequality work?
I added an edit to my answer which hopefully answers your question a little bit better.
Feb
21
revised How does this proof of the Cauchy-Schwarz Inequality work?
added 1116 characters in body
Feb
20
reviewed Approve How does this proof of the Cauchy-Schwarz Inequality work?
Feb
20
answered How does this proof of the Cauchy-Schwarz Inequality work?
Feb
20
comment How does this proof of the Cauchy-Schwarz Inequality work?
The maximum or minimum of a quadratic $Ax^2+Bx+C$ occurs at $-\frac{B}{2A}$. In this case, $A=a$ and $B=-b$.
Feb
18
answered Is -1 less than 0.1?
Feb
10
reviewed Approve Convergence of a telescoping series divided by another series
Jan
25
awarded  Popular Question
Jan
18
accepted Is the construction of $\mathbb{R}$ by Cauchy sequences due to Cauchy? For that matter, are Cauchy sequences due to Cauchy?
Jan
18
asked Is the construction of $\mathbb{R}$ by Cauchy sequences due to Cauchy? For that matter, are Cauchy sequences due to Cauchy?
Jan
9
answered Fixed point of tree automorphism
Jan
9
reviewed Approve Polar form of quadratic equations
Jan
9
answered Why is Euclid's proof on the infinitude of primes considered a proof?
Dec
23
comment Find x, when F(x) is a cdf with given mean and std
Right, that does not fully specify a distribution though. Lots of random variables have that same mean and standard deviation but have different distributions and hence would have a different solution for $x$. I'll assume that in this case it is a normal random variable, but in general it could be anything so you should say that it's normal.
Dec
23
comment Find x, when F(x) is a cdf with given mean and std
is that comma a decimal point in "0,8"? Also, what kind of distribution does $X$ have?
Dec
23
reviewed Approve Sequential sums $1+2+\cdots+N$ that are squares
Dec
22
answered Why can $y-y_1 = m(x-x_1)$ describe a line but $m=(y-y_1)/(x-x_1)$ is missing a point?
Dec
20
answered Wolfram Alpha unexpected answer.
Dec
20
comment Show that a continuous function with a certain integral property must be f(x)=x.
note that you don't have any assumptions about differentiability so, strictly speaking, integration by parts isn't available to you