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bio website linkedin.com/in/gt6989b
location New York, NY
age 35
visits member for 2 years, 11 months
seen 16 hours ago

Apr
9
comment What is the shortest way to write the number $1234567890$?
One approach is to find some relatively short base, and it shrinks fast, e.g. it is $499602D2_{16}$ (same 10 digits).
Apr
9
comment Evaluate the limit
@rubik Missed the all real numbers part, thank you
Apr
9
comment Suppose $A, B$, and C are sets. Prove that $C\subset A\Delta B \Leftrightarrow C \subset A \cup B$ and $A \cap B \cap C = \emptyset $
@GabeCarr not sure what you mean. The event $z \in X - Y = X \cap \bar{Y}$ happens if and only if $z \in X$ and $z \not \in Y$.
Apr
9
comment Probability of eight dice showing sum of 9, 10 or 11
Looks right to me
Apr
9
comment Evaluate the limit
Why cannot you have $$\psi(x) = 2 + \frac{1}{x} \to 2$$ instead? By this example it can converge to any limit...
Apr
9
comment Evaluate the limit
I don't understand what the second condition adds: since $t^2 < (t+1)^2$, we already know that $$\psi(t^2) > \psi(t^2+1) > \ldots > \psi\left((t+1)^2\right)$$
Apr
9
comment How to find maximum/minimum of $y=\frac{x(x^2-x+2)}{x^2-9}$?
@Cherufe both min and max are unbounded
Apr
9
comment Line integral segment of parabola
@user131040 please be more specific, i am not telling you the answer. But will comment on what you are doing exactly if you tell me the steps you took. What are you using for $x,y$ and which integral are you taking?
Apr
8
comment Line integral segment of parabola
@user131040 i thought the text specified this pretty clearly
Apr
8
comment Line integral segment of parabola
@user131040 You must express them in terms of $t$, as we defined when we parameterized the curve.
Apr
8
comment How to find maximum/minimum of $y=\frac{x(x^2-x+2)}{x^2-9}$?
@Cherufe As $x \to \pm \infty$ there cannot be problems with any finite values of $x$...
Apr
8
comment Is $(A+B)^2 = A^2 + B^2$ if $A$ and $B$ are matrices
Moreover, you proved OP's statement is true iff $AB = -BA$.
Apr
7
comment show that if $\displaystyle\lim_{n \to \infty} f(n+x)=0$ then $\displaystyle\lim_{x \to \infty}f(x)=0$
Welcome to Math.SE! Could you please post some of your thoughts to approach the problem and we will be glad to give hints and comments.
Apr
3
comment Solving inequalities with absolute values on both sides
@Joseph By the way, formally, the intersection between sets is never zero, but rather is said to be empty.
Apr
3
comment Solving inequalities with absolute values on both sides
@Joseph please see the edit
Apr
3
comment Solving inequalities with absolute values on both sides
@Joseph yes, they go by intersection. The second inequality splits, e.g. into $(2x-1) + |1-x| \ge 3$ and $-(2x-1) + |1-x| \ge 3$.
Apr
3
comment Evaluate the geometric series or state that it diverges.
@Mahina You compute the terms by "plugging in" the values $k=1,2,3$ into the formula in the sum: $4\left(\frac{-1}{5}\right)^{4\cdot 1}, 4\left(\frac{-1}{5}\right)^{4\cdot 2}, 4\left(\frac{-1}{5}\right)^{4\cdot 3}$. Simplify these, and then you get first term to be $a$ and ratio to be $r$. Check that ratio of 2nd/1st and 3rd/2nd terms is the same.
Apr
3
comment Evaluate the geometric series or state that it diverges.
@Mahina Ignore? Why? Write out the first three terms, what are they?
Apr
3
comment Have some trouble with limits
Do you know about Taylor series? That would help a lot with (3) and (4). Factor the denominator of (2) at $a^3-b^3$ with $a = \sqrt[3]{x}, b= 1$.
Apr
2
comment Can a transcendental number be an infimum of a set of rationals?
@user2345215 i thought it is generally known that any non constant algebraic functions of 1 variable, applied to a transcendetal number, yield transcendental output.