5,775 reputation
31747
bio website ophirgame.com
location United States
age 71
visits member for 3 years, 1 month
seen 2 days ago

(update) - I'm having a board game published! We'd appreciate your support on Facebook or on Twitter, as we prepare for a Kickstarter campaign in early 2014.


I hereby commit to contributing to this site without any rudeness, sarcasm, accusation, or any other unloving speech.


Nov
1
comment Logic Riddle - Multiple Choice
The first is E. You move from one picture to the next by rotating one stick a quarter turn to the left.
Nov
1
comment Complex number: Roots
Let $z = x + iy $ in the second one and use the definition of absolute value.
Nov
1
comment Logial Entailment vs. Material Conditional: binding free variables?
Also, en.wikipedia.org/wiki/Vacuous_truth
Nov
1
comment Area under the curve
The integral gives signed area. Also, what's the function for the ellipse?
Nov
1
comment If $f(x)=\int_0^x x^2 \sin {t^2}~dt $, find $f'(x)$.
Yes! Good luck to you.
Nov
1
comment Logarithmic function
@user: you might consider editing your question to include the above comment. That kind of thought/effort is highly sought after!
Nov
1
comment If $f(x)=\int_0^x x^2 \sin {t^2}~dt $, find $f'(x)$.
You really should think about the Bonus question though! It requires the chain rule...
Nov
1
comment Determinant from matrix entirely composed of variables
Do not underestimate the power of laziness! :)
Nov
1
comment If $f(x)=\int_0^x x^2 \sin {t^2}~dt $, find $f'(x)$.
Almost. Your first term should be $x^2 \sin (x^2)$.
Nov
1
comment Determinant from matrix entirely composed of variables
No love for theory? What if it's a $5 \times 5$ matrix ?? ;)
Nov
1
comment Determinant from matrix entirely composed of variables
Sure, but there are theoretical reasons. See property 7
Nov
1
comment If $f(x)=\int_0^x x^2 \sin {t^2}~dt $, find $f'(x)$.
Since the integral is with respect to a different variable, $t$, you can treat the $x^2$ as a constant and write the integral as $$x^2 \cdot \int_0^x sin(t^2)dt$$
Nov
1
answered Determinant from matrix entirely composed of variables
Nov
1
answered If $f(x)=\int_0^x x^2 \sin {t^2}~dt $, find $f'(x)$.
Nov
1
comment If $f(x)=\int_0^x x^2 \sin {t^2}~dt $, find $f'(x)$.
Pull out the $x^2$, then use the product rule and the fundamental theorem of calculus.
Oct
29
revised Please explain in detail how to prove $\lim_{x\to 1} x^2 + 2x +3 = 6$ using only the definition of limit
rolled back to a previous revision
Oct
28
comment Cauchy Integral formula question
A reasonable interpretation of the notation would suggest that the contour is $|z-i|=1$, traversed once counterclockwise.
Oct
28
comment If $n^2+10$ is odd then $n$ is odd.
Related: math.stackexchange.com/questions/528811/…
Oct
27
comment When does $f(a),f(f(a)),f(f(f(a)))…$ produce better and better approximations to $x=f(x)$?
Isn't your function Lipschitz continuous?
Oct
27
comment When does $f(a),f(f(a)),f(f(f(a)))…$ produce better and better approximations to $x=f(x)$?
I would also appreciate a different phrasing of this question. You know, for those of us who are easily confused...