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Jul
26
answered Prove that $16 \cos 12^\circ ·\cos 24^\circ ·\cos 48^\circ· \cos 96^\circ ·\cos 192^\circ = 1$
Jul
26
answered Prove that $16 \cos 12^\circ ·\cos 24^\circ ·\cos 48^\circ· \cos 96^\circ ·\cos 192^\circ = 1$
Jul
26
answered Find limit of fraction without derivatives
Jul
26
comment Evaluating the alternating series $\sum_{n = 1}^\infty \frac {(-1)^{n-1}}{3^{n-1}}$
@LeoMatyushkin, See also : en.wikipedia.org/wiki/Geometric_series#Proof_of_convergence
Jul
26
comment Evaluating the alternating series $\sum_{n = 1}^\infty \frac {(-1)^{n-1}}{3^{n-1}}$
@LeoMatyushkin, Definitely. Hope you understand the start index does not matter
Jul
26
answered Evaluating the alternating series $\sum_{n = 1}^\infty \frac {(-1)^{n-1}}{3^{n-1}}$
Jul
26
comment Formulas related to acceleration
school-for-champions.com/science/…
Jul
26
answered Formulas related to acceleration
Jul
26
comment prove $a^2_o-a^2_1+a^2_2-…+(-1)^{n-1}a^2_{n-1}=\frac {1}{2}(a_n+(-1)^{n+1}a^2_n)$
I think, $$0\le k\le 2n$$
Jul
26
comment Prove that $\sin(12^\circ)\sin(48^\circ)\sin(54^\circ)=\frac18$
@Kanishk, Proof is here(cut-the-knot.org/arithmetic/algebra/sin3x.shtml). Also related : math.stackexchange.com/questions/503575/…
Jul
26
comment Prove that $\sin(12^\circ)\sin(48^\circ)\sin(54^\circ)=\frac18$
@Tunk-Fey, $$(3)\implies\cos36^\circ-\cos72^\circ=\frac12$$ (math.stackexchange.com/questions/827540/…)
Jul
26
answered number of ordered pairs of integers (x,y) satisfying the equation
Jul
26
answered In a triangle ABC, prove that cot(A/2)+cot(B/2)+cot(C/2) =cot(A/2)cot(B/2)cot(C/2)
Jul
26
comment Prove that $\small\sin x\sin y\sin(x-y) + \sin y \sin z \sin(y-z) + \sin z \sin x \sin(z-x) + \sin(x-y) \sin(y-z) \sin(z-x) = 0$.
math.stackexchange.com/questions/864895/…
Jul
26
answered In a triangle ABC, prove that cot(A/2)+cot(B/2)+cot(C/2) =cot(A/2)cot(B/2)cot(C/2)
Jul
26
comment number of solution to the given equation.
@user2235487, My pleasure. Typo rectified
Jul
26
revised number of solution to the given equation.
deleted 1 character in body
Jul
26
answered number of solution to the given equation.
Jul
26
revised finding mod of an expression with variables
added 191 characters in body
Jul
26
answered finding mod of an expression with variables