Step by Step Solution
Step by step solution :
Step 1 :
Equation at the end of step 1 :
(3x2 • x) - 2 = 0Step 2 :
Trying to factor as a Difference of Cubes:
2.1 Factoring: 3x3-2
Theory : A difference of two perfect cubes, a3 - b3 can be factored into
(a-b) • (a2 +ab +b2)
Proof : (a-b)•(a2+ab+b2) =
a3+a2b+ab2-ba2-b2a-b3 =
a3+(a2b-ba2)+(ab2-b2a)-b3 =
a3+0+0-b3 =
a3-b3
Check : 3 is not a cube !!
Ruling : Binomial can not be factored as the difference of two perfect cubes
Polynomial Roots Calculator :
2.2 Find roots (zeroes) of : F(x) = 3x3-2
Polynomial Roots Calculator is a set of methods aimed at finding values of x for which F(x)=0
Rational Roots Test is one of the above mentioned tools. It would only find Rational Roots that is numbers x which can be expressed as the quotient of two integers
The Rational Root Theorem states that if a polynomial zeroes for a rational number P/Q then P is a factor of the Trailing Constant and Q is a factor of the Leading Coefficient
In this case, the Leading Coefficient is 3 and the Trailing Constant is -2.
The factor(s) are:
of the Leading Coefficient : 1,3
of the Trailing Constant : 1 ,2
Let us test ....
P | Q | P/Q | F(P/Q) | Divisor | |||||
---|---|---|---|---|---|---|---|---|---|
-1 | 1 | -1.00 | -5.00 | ||||||
-1 | 3 | -0.33 | -2.11 | ||||||
-2 | 1 | -2.00 | -26.00 | ||||||
-2 | 3 | -0.67 | -2.89 | ||||||
1 | 1 | 1.00 | 1.00 | ||||||
1 | 3 | 0.33 | -1.89 | ||||||
2 | 1 | 2.00 | 22.00 | ||||||
2 | 3 | 0.67 | -1.11 |
Polynomial Roots Calculator found no rational roots
Equation at the end of step 2 :
3x3 - 2 = 0
Step 3 :
Solving a Single Variable Equation :
3.1 Solve : 3x3-2 = 0
Add 2 to both sides of the equation :
3x3 = 2
Divide both sides of the equation by 3:
x3 = 2/3 = 0.667
When two things are equal, their cube roots are equal. Taking the cube root of the two sides of the equation we get:
x = ∛ 2/3
The equation has one real solution
This solution is x = ∛ 0.667 = 0.87358
One solution was found :
x = ∛ 0.667 = 0.87358How did we do?
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