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Last updated on January 10th, 2025
The cube root of 9 is the value that, when multiplied by itself three times (cubed), gives the original number 9. Do you know? Cube roots apply to our real life also, like that for measuring volume and scaling, density and mass calculation, etc.
The cube root of 9 is 2.08008382305. The cube root of 9 is expressed as ∛9 in radical form, where the “∛" sign is called the “radical” sign. In exponential form, it is written as (9)⅓. If “m” is the cube root of 9, then, m3=9. Let us find the value of “m”.
The Prime Factorization of 9 is 3×3, so, the cube root of 9 is expressed as ∛9 as its simplest radical form. We can find the cube root of 9 through another method, named as, Halley’s Method. Let us see how it finds the result.
Now, what is Halley’s Method? It is an iterative method for finding cube roots of a given number N, such that, x3=N, where this method approximates the value of “x”.
Formula is ∛a≅ x((x3+2a) / (2x3+a)), where
a=given number whose cube root you are going to find
x=integer guess for the cubic root
Let us apply Halley’s method on the given number 9.
Step 1: Let a=9. Let us take x as 2, since, 23=8 is the nearest perfect cube which is less than 9.
Step 2: Apply the formula. ∛9≅ 2((23+2×9) / (2(2)3+9)) = 2.08
Hence, 2.08 is the approximate cubic root of 9.
below given some common mistakes and how to avoide them:
Find ∛64/ ∛9
∛64/ ∛9
= 4 / 2.08
=1.923
Answer: 1.923
We know that the cubic root of 64 is 4, hence dividing 4 by ∛9.
If y = ∛9, find y³.
y=∛9
⇒ y3= (∛9)3
⇒ y3= 9
Answer: 9
(∛9)3=(91/3)3=9. Using this, we found the value of y3.
Subtract ∛9 - ∛8
∛9-∛8
= 2.08–2
= 0.08
Answer: 0.08
We know that the cubic root of 8 is 2, hence subtracting ∛8 from ∛9.
What is ∛(9⁶) ?
∛(96)
= ((9)6))1/3
=( 9)2
= 81
Answer: 81
We solved and simplified the exponent part first using the fact that, ∛9=(9)⅓, then solved.
Find ∛(9+18).
∛(9+18)
= ∛27
=3
Answer: 3
Simplified the expression, and found out the cubic root of the result.
Jaskaran Singh Saluja is a math wizard with nearly three years of experience as a math teacher. His expertise is in algebra, so he can make algebra classes interesting by turning tricky equations into simple puzzles.
: He loves to play the quiz with kids through algebra to make kids love it.