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May
14
comment Establishing the Trigonometric Idenitity
Use $$\sin^2\theta+\cos^2\theta=1$$
May
13
comment Extracting real and imaginary numbers from a complex number
@columbus8myhw, Do you mean $n=0$?
May
13
revised How to prove this logarithm equation?
added 92 characters in body
May
13
answered How to prove this logarithm equation?
May
13
comment Extracting real and imaginary numbers from a complex number
@DinRevah, $$\dfrac{x+iy}n=\dfrac xn+i\dfrac yn$$ for $x,y,n$ are real numbers
May
13
answered Evaluating natural limit
May
13
answered Extracting real and imaginary numbers from a complex number
May
13
answered $ \lim_{n\to\infty} \sum_{k=1}^{n} \frac{1}{4n - \frac{k^2}{n}} $ appears to disagree with $\int_0^1 \frac{dx}{4-x^2}$
May
13
comment Find the sum $\sum_{k=1}^n k(k+1)2^k$
For $$\sum 2^k(a_0+a_1k+a_2k^2)$$ should we start with $$2^k(b_0+b_1k+b_2k^2)$$ ?
May
13
comment Find the sum $\sum_{k=1}^n k(k+1)2^k$
How to find the initial form of $f(k)$. For example what if the summation were $$\sum_{k=1}^nk(4+k)2^k$$
May
13
answered Find the sum $\sum_{k=1}^n k(k+1)2^k$
May
13
answered $\lim_{x\rightarrow0}\frac{\ln\cos2x}{\left(2^{x}-1\right)\left(\left(x+1\right)^{5}-\left(x-1\right)^{5}\right)}$
May
13
comment Find the limit $\lim_{n\rightarrow\infty}\sum_{k=1}^{n}\frac{1}{k+n}$
@Mirak, Observe that extracting $1/n$ gives us $f(k/n)$
May
13
answered Find the limit $\lim_{n\rightarrow\infty}\sum_{k=1}^{n}\frac{1}{k+n}$
May
11
answered How do I differentiate $\cos^2 (2x)?$
May
11
answered Imroper integral. Show that this expresions are…
May
11
comment How to solve congruence modulo equations?
@justin, We need to find a value of $y$ such that $3|(26y-1)$ . By observation, $y=2$ is one of such values
May
11
comment Show the congruence $x^{p-1}\equiv 1\pmod{p}$ has $p-1$ solutions
See math453fall2008.wikidot.com/lecture-23
May
11
comment How to solve congruence modulo equations?
@justin, As $52\equiv0\pmod{26},51\equiv-1$
May
11
answered Find the values of $x$ satisfying $\sin^{-1}(|\sin x|)-\cos^{-1}(\cos x)\ge0$ in $[0, 2\pi]$