Math Is Fun Forum

mel179

Guest

Solving cubic equation

[math]Hi there!

I forgot most of my math from school and uni and now I want to calculate the mesh size of a porous gel.
I came up with this equation:

x^3 = 0.8 (a+x)^3

I measured all values for a using nanoindentation so I need to solve this equation for x.
Could anybody help please?

Thanks a lot

Bob

Administrator

Registered: 2010-06-20

Posts: 10,646

Re: Solving cubic equation

hi mel179

Welcome to the forum.

Cube root both sides

note: cube root of 0.8 is approximately 0.9283. 
On a calculator press the y^x button (some calcs show incorrectly as x^y) with (1/3) as the y value. 
ie. 0.8 y^x (1/3)

Hope that's what you need. 

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

mel179

Guest

Re: Solving cubic equation

Wow! I didn't expect it to be so easy, that's embarrassing for me.

Thank you so much!!!! You made my day