Quispiam
Reputation
498
Next privilege 500 Rep.
Access review queues
 May 22 comment Choice of numbers in calculating $\lim_{x\rightarrow 0}\frac{e^{2x}-1}{\sin 3x}$ Ah, yes, I meant 2x, question is updated. Jan 19 comment Approaching infinity with volume of turning body The answer is $2\pi\left[ \ln \frac{t}{t+1} + \frac{1}{t+1} \right ]_1^\sqrt{w}$ Jan 19 comment Approaching infinity with volume of turning body That's my thinking, yes, but it doesn't seem to be it according to the text book answer. Sep 16 comment Finding correlation through plotting logarithms I added the values. Sep 16 comment Finding correlation through plotting logarithms I need to find a correlation between the values that result in the $x$ and $y$ axes. I can edit and add the values, but it's more about understanding how to solve this type of problem, than to solve this specific problem with those specific values. Sep 14 comment Found one root, how do I know to keep searching or not? Hm, yes, thanks. Still not sure how I managed to get it so wrong. Thanks! Sep 13 comment Finding $\alpha$ for $\sin(4 \alpha + \frac{\pi}{6}) = \sin (2\alpha + \frac{\pi}{5})$ I don't quite get your final line. When calculating $\frac{2\alpha + \frac{\pi}{30}}{2}$ I get $\alpha = n\pi + \frac{\pi}{60}$. Am I missing a step or something? Sep 12 comment Calculate $\cos(v+\frac{\pi}{6})$ when $\cos v = -\frac{2}{3}$ This helped a lot, I found the answer and it seems to be correct ($-\frac{2\sqrt{3}+\sqrt{5}}{6}$). Thank you! Aug 30 comment Calculating the chess problem, sum $\sum_{k=0}^{63}2^{k}$ Discovered my mistake - it was supposed to be $2^{64} - 1$, not $2^{64} + 1$. Aug 25 comment Finding all $x$ for $\frac{2x - 13}{2x + 3} \lt \frac{15}{x}$ It seems I figured everything out now. It was part of a bigger problem (uniting it with another inequality) and it seems like everything goes together perfectly now. Thanks a lot for the help. Aug 25 comment Finding all $x$ for $\frac{2x - 13}{2x + 3} \lt \frac{15}{x}$ Sorry, that was me being too excited after suddenly getting things right for once. Should have kept checking for roots after finding the obvious one. Thank you. Aug 25 comment Finding all $x$ for $\frac{2x - 13}{2x + 3} \lt \frac{15}{x}$ Thank you! Calculating for case (2) I find the root $-1$ for $2x^2 - 43x - 45$. Adding this to the roots of $2x(x+\frac{3}{2})$, this should mean that the entire expression is negative when $\frac{-3}{2} \lt x \lt -1$ or $0 \lt x$. However, when testing higher numbers (approximately where $x \gt 22$), $2x^2 - 43x - 45$ becomes positive and so the entire expression becomes positive. Why is this? Aug 25 comment Finding all $x$ for $\frac{2x - 13}{2x + 3} \lt \frac{15}{x}$ Thank you. Correction, though - the $45$ should be negative. Aug 24 comment How to find $k$'s quotient of $\frac{-18}{(-2)^k}$ Thank you, I see now. But don't you mean $\frac{a(r^{n+1}-1)}{r-1}$? Or am I mistaken? Aug 24 comment Getting wrong result calculating sums I can't believe I missed such a simple mistake. Thank you! Aug 20 comment Finding a value for $x$ when there should be none @AndréNicolas Ah, yes, I see. Thank you. Aug 20 comment Finding a value for $x$ when there should be none @AndréNicolas You mean dividing by $0$? Aug 20 comment Finding a value for $x$ when there should be none This is the second time in a row I've been stuck on a problem simply because I forgot about the zero-divide no-no. :/ Thanks. Aug 18 comment Calculating $x$ from $x^3 = 2x^2 - x$, getting wrong result Thanks! It never struck me that $x$ could be $0$ and that I discounted that possibility so easily. Aug 18 comment Calculating $x$ from $x^3 = 2x^2 - x$, getting wrong result I did actually try $x=1$ in the original equation, but were confused as I was supposed to find two separate for $x$. I didn't even stop to think it could be $0$. Thanks!