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Martin Cohen is a retired computer programmer who loves dancing (favorites are West Coast Swing, Waltz, Foxtrot, and Salsa), writing (but not revising) poems, and solving math problems (that's why I'm here). He is currently trying to learn improv at the Westside Comedy Theater (westsidecomedy.com) in Santa Monica, CA.

He can also be reached at mjcohen@acm.org.


2d
comment Is it easier to find $a^2-8c=b^2$ than $a^2-c=b^2$
@user314: You do not get a Pell equation, since that requires the values to be integers.
2d
comment Is it easier to find $a^2-8c=b^2$ than $a^2-c=b^2$
If $8c^2 = 133^2-39^2 = (133-39)(133+39) = 94*172 = (2*47)*(4*43)$, so $c^2 = 47*43$ which is not a square.
2d
comment Finding $a$ and $b$ so that the function is continuous
a and b just happen to be equal.
2d
comment Let $f(x)=x^2+12x+30$. Solve $f(f(f(f(f(x)))))=0$
I think that this is the way Vieta did it, although with cosine of multiple angles.
2d
answered Is it easier to find $a^2-8c=b^2$ than $a^2-c=b^2$
2d
answered If there is an $x$ such that $(2x_n)$ converges, does this imply that $(x_n)$ is also convergent?
2d
comment Is it easier to find $a^2-8c=b^2$ than $a^2-c=b^2$
What is your method?
2d
answered Big O and Big Omega Proof with lg base 2
2d
awarded  Good Answer
Jan
28
answered Is there are integer solutions for this equation: $ 65x-4y= 129$
Jan
28
answered is it possible to intergrate this function to get x(t) and y(t)?
Jan
27
comment Expansion $ f (x) = \ln^ 2 x$. Taylor.
$\ln(x^2) = 2\ln(x)$, so it is much easier.
Jan
27
answered Evaluate the Limit $\lim_{x\to 0} {\left((e^x - (1+x)) \over x^n\right)}$
Jan
27
comment Infinite Sum with differential operator
Changed my answer to reflect your one-letter change.
Jan
27
revised Infinite Sum with differential operator
Problem changed
Jan
27
answered Infinite Sum with differential operator
Jan
27
answered What is $c$ in $\left\lfloor\frac{a}{bc}\right\rfloor=d$
Jan
26
comment For what values is my integral diverging or converging?
I might have. Feel free to submit a corrected answer.
Jan
26
comment is there constant $k$ such that nth fibonnaci number $F_n$ satisfies $F_n > k2^n$ and vice versa?
I don't see why this question was put on hold. The context seems perfectly clear to me.
Jan
26
answered is there constant $k$ such that nth fibonnaci number $F_n$ satisfies $F_n > k2^n$ and vice versa?