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How to do cube roots.

JamieLam

New member
Jan 16, 2014
6
This is a simple question. The problem I'm facing is A cube plus B cube = 22 C cube
A cube plus B cube over 22 = C cube
At this junction I like to ask if I want to cuberoots both sides, will the 22 be cube root as well? I'm sorry to bother since I forgot my basics. I don't want solutions to the problem. I only want to know about the cube rooting. Thanks!
 

Fantini

"Read Euler, read Euler." - Laplace
MHB Math Helper
Feb 29, 2012
342
Yes, you will have to cube the 22 as well. What you have is

$$\frac{A^3 + B^3}{22} = C^3.$$

If you cube both sides you realize that 22 can't be neglected. :)
 

HallsofIvy

Well-known member
MHB Math Helper
Jan 29, 2012
1,151
Fantini said "cube" but I am sure he meant "cube root".

If [tex]C^3= \frac{A^3+ B^3}{22}[/tex]
then [tex]C= \sqrt[3]{\frac{A^3+ B^3}{22}}= \frac{\sqrt[3]{A^3+ B^3}}{\sqrt[3]{22}}[/tex].

I hope you understand that [tex]\sqrt[3]{A^3+ B^3}[/tex] is NOT the same a A+ B!