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1d
accepted Prove $f(x+y)=f(x)+f(y)$ and $f(cx)=cf(x)$
1d
comment Prove $f(x+y)=f(x)+f(y)$ and $f(cx)=cf(x)$
If we mean the same thing for (3) . $\forall r \in \mathbb R$
1d
comment Prove $f(x+y)=f(x)+f(y)$ and $f(cx)=cf(x)$
I have seen these proofs but my dificulty is proving for $\mathbb R$ not $\mathbb Z$ or $\mathbb Q$
1d
comment Prove $f(x+y)=f(x)+f(y)$ and $f(cx)=cf(x)$
Ok I edited it .
1d
revised Prove $f(x+y)=f(x)+f(y)$ and $f(cx)=cf(x)$
added 28 characters in body
1d
asked Prove $f(x+y)=f(x)+f(y)$ and $f(cx)=cf(x)$
2d
comment Root with bolzano theorem
cause theory has < . it makes sense but formally not
2d
asked Root with bolzano theorem
Jan
27
accepted Limit find $f(x)$ $ \lim_{x\to1}\frac{f(x)\cos{\frac{\pi x}{2}}}{\sqrt[3]x-1}=3 $
Jan
27
comment Limit find $f(x)$ $ \lim_{x\to1}\frac{f(x)\cos{\frac{\pi x}{2}}}{\sqrt[3]x-1}=3 $
Just solving some before LHospital problems and want to learn without it too...
Jan
27
comment Limit find $f(x)$ $ \lim_{x\to1}\frac{f(x)\cos{\frac{\pi x}{2}}}{\sqrt[3]x-1}=3 $
It seems the key was there to change cos to sin. I should have thought it...
Jan
27
comment Limit find $f(x)$ $ \lim_{x\to1}\frac{f(x)\cos{\frac{\pi x}{2}}}{\sqrt[3]x-1}=3 $
hm yep, however I have added without l'Hospital tag. Any idea there ?
Jan
27
asked Limit find $f(x)$ $ \lim_{x\to1}\frac{f(x)\cos{\frac{\pi x}{2}}}{\sqrt[3]x-1}=3 $
Jan
27
accepted Series proof $\sum_1^\infty|a_n|<\infty$ then show that $\sum_1^\infty{a_n^2}<\infty$
Jan
27
comment Series proof $\sum_1^\infty|a_n|<\infty$ then show that $\sum_1^\infty{a_n^2}<\infty$
I am going to ask why it is poor but probably he isnt going to tell me(cant insist he'll get annoyed).However after asking lots of other classmates someone showed me the solution . It is like this math.stackexchange.com/a/493782/17446 .
Jan
26
comment Limit evaluation $\lim_\limits{x\to2}\frac{\sqrt{12-x^3}-\sqrt[3]{x^2+4}}{x^2-4}$
seems possible but hard
Jan
26
comment Limit evaluation $\lim_\limits{x\to2}\frac{\sqrt{12-x^3}-\sqrt[3]{x^2+4}}{x^2-4}$
very smart... wow
Jan
26
accepted Limit evaluation $\lim_\limits{x\to2}\frac{\sqrt{12-x^3}-\sqrt[3]{x^2+4}}{x^2-4}$
Jan
26
comment Limit evaluation $\lim_\limits{x\to2}\frac{\sqrt{12-x^3}-\sqrt[3]{x^2+4}}{x^2-4}$
yes I am sure...
Jan
26
comment Limit evaluation $\lim_\limits{x\to2}\frac{\sqrt{12-x^3}-\sqrt[3]{x^2+4}}{x^2-4}$
Sorry but without this