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Здравствуйте!

I am learning mathematics to help further mathematical development in my country.


Jul
21
comment Prove the reflexivity of $\subseteq$.
@GitGud Yes, but what you mean with "eliminating the universal quantifier"? Is there a process to do it or I just need to throw it away?
Jul
21
comment Prove the reflexivity of $\subseteq$.
@GitGud I don't really know. I've imagined some things but none of them is nice. I remember of the "getting hid of $\forall x$", I've heard a small piece about it in a lecture but I had to leave and didn't get the rest.
Jul
21
comment Prove the reflexivity of $\subseteq$.
@GitGud Excuse me. But what's the difference of $\forall$ and "take an arbitrary $x$"?
Jul
20
comment Is there something that studies equivalent forms of writing and expression?
@JHance Yes, thanks.
Jul
16
comment What do we lose by differentiating without using the rules of differential calculus?
Good point you made in your first sentence. There are rules that are more primitive and these can be used to derive the others, right?
Jul
12
comment Differentiating $\frac{te^{\tan t}}{ln(3t+1)}$?
Excuse me, you wrote "$f_2'\cdot f_1'$ is trivial", shouldn't it be $f_2\cdot f_1'$?
Jul
11
comment Differentiating $\frac{te^{\tan t}}{ln(3t+1)}$?
I am a little confused on this: You need to either use the chain and product rules within the quotient rule using the formula for the quotient rule or use just one large product rule. - Could you show it to me?
Jul
11
comment Differentiating $\frac{te^{\tan t}}{ln(3t+1)}$?
I used the chain rule, using that approach, what should be done next?
Jul
11
comment Differentiating $\frac{te^{\tan t}}{ln(3t+1)}$?
So I should use one of them or the other but not both?
Jul
10
comment Differentiating $\frac{te^{\tan t}}{ln(3t+1)}$?
Then I didn't need to use the chain rule on $e^{\tan(x)}$?
Jul
10
comment Differentiating $\frac{te^{\tan t}}{ln(3t+1)}$?
@TylerHG Thanks for the heads up.
Jul
10
comment Differentiating $\frac{te^{\tan t}}{ln(3t+1)}$?
Thanks for the help. But the way I was doing would also work, wouldn't it? (No, I'm not planning to use it, I'm just making the stupidity test on myself).
Jul
10
comment Differentiating $\frac{te^{\tan t}}{ln(3t+1)}$?
@TylerHG Yes. It was a poor adaptation from portuguese. I thought one could employ "derive" in english.
Jun
27
comment Are there non-trivial systems of arithmetic in which the order of precedence of the operators does not change the output?
@Thoth19 Thanks for the heads up!
Jun
27
comment What's the importance of a formula for the real and imaginary parts of a complex number?
I see. I still didn't read about complex numbers expressed in that way. I just discovered a few seconds ago that they are called complex numbers in the exponential form.
Jun
23
comment Good textbooks and articles from arXiv for undergraduate students?
@Zircht Sorry, I've downloaded the source and tried to open without success. Any hints?
Jun
17
comment Is there a garden of derivatives?
@DaveL.Renfro Great! But why didn't you answered it instead of commenting(so I can upvote you)?
Jun
11
comment $\frac{|| \overline{AM}||}{|| \overline{AB}||}=\frac{|| \overline{AN}||}{|| \overline{AC}||}=\frac{|| \overline{MN}||}{|| \overline{BC}||}$
Can you expand a little more on how did you get these steps? I'm a little lost.
Jun
11
comment $\frac{|| \overline{AM}||}{|| \overline{AB}||}=\frac{|| \overline{AN}||}{|| \overline{AC}||}=\frac{|| \overline{MN}||}{|| \overline{BC}||}$
I didn't get why you assumed that $\overrightarrow{AM}+\overrightarrow{AN}+\overrightarrow{MN}=0$.
Jun
11
comment $\frac{|| \overline{AM}||}{|| \overline{AB}||}=\frac{|| \overline{AN}||}{|| \overline{AC}||}=\frac{|| \overline{MN}||}{|| \overline{BC}||}$
@Duncan Show that $\frac{|| \overrightarrow{AM}||}{|| \overrightarrow{AB}||}=\frac{|| \overrightarrow{AN}||}{|| \overrightarrow{AC}||}=\frac{|| \overrightarrow{MN}||}{|| \overrightarrow{BC}||}$.