Finding a cube root of a number without using calculator .

[Emmanuel_Euler]

HI EVERYONE
I was thinking if we could find a cube root without using a calculator.
square root was easy to find without calculator,but cube root i have no idea to find it.
any help??
for example(cube root of 3 or 2)

 

[Emmanuel_Euler]

finding a square root without using calculator.

 

[Mark44]

Try this link: http://www.mathpath.org/Algor/cuberoot/algor.cube.root.htm

You might find it interesting that when I was in the 8th or 9th grade, we were taught how to calculate square roots by the method shown in the video you posted. That was before calculators were invented...

 

[Svein]

A numerical recipe for calculating $\sqrt[3]{a}$. Set $x_{1}=\frac{a}{3}$ and recursively calculate $x_{n+1}=\frac{1}{3}(2x_{n}+\frac{a}{x_{n}^{2}})$. Stop when |x_n+1 - x_n| is "small enough".

 

[Emmanuel_Euler]

Thank you so much for help.