Solving limit $ \lim_{x\rightarrow 1}\left(\frac{\sqrt[3]{7+x^3}-\sqrt[2]{3+x^2}}{x-1}\right) $ without L'Hopital.

465 Views Asked by At

I was trying all the day to resolve this problem with different method without L'Hopital but I can't do it, I would really like to up my mathematical development but the post doesn't allow me because I have less than 10 of reputation to up a image, so here is a link to one of me best try

$$ \lim_{x\rightarrow 1}\left(\frac{\sqrt[3]{7+x^3}-\sqrt[2]{3+x^2}}{x-1}\right) $$

2

There are 2 best solutions below

2
On BEST ANSWER

Hint: Use the (rather lengthy, but perfectly working) identity $$a-b=\frac{a^6-b^6}{a^5+a^4b+a^3b^2+a^2b^3+ab^4+b^5}$$

0
On

$$\lim_{x\to1}\dfrac{(7+x^3)^{1/3}-2}{x-1}=\dfrac{d(7+y^3)^{1/3}}{dy}_{(\text{ at }y=1)}=?$$