Descartes' Rule of Signs Calculator
Apply Descartes' rule of signs step by step
The calculator will find the maximum number of positive and negative real roots of the given polynomial using Descartes' rule of signs, with steps shown.
Solution
Your input: find the number of real roots of $$$x^{5} - 2 x^{4} - 12 x^{3} - 12 x^{2} - 13 x - 10$$$ using the Descartes' Rule of Signs.
The rule states that if the terms of a single-variable polynomial with real coefficients are ordered by descending variable exponent, then the number of positive roots of the polynomial is either equal to the number of sign differences between consecutive nonzero coefficients, or is less than it by an even number.
So, the coefficients are $$$1, -2, -12, -12, -13, -10$$$.
As can be seen, there is $$$1$$$ change.
This means that there is $$$1$$$ positive real root.
To find the number of negative real roots, substitute $$$x$$$ with $$$- x$$$ in the given polynomial: $$$x^{5} - 2 x^{4} - 12 x^{3} - 12 x^{2} - 13 x - 10$$$ becomes $$$- x^{5} - 2 x^{4} + 12 x^{3} - 12 x^{2} + 13 x - 10$$$.
The coefficients are $$$-1, -2, 12, -12, 13, -10$$$.
As can be seen, there are $$$4$$$ changes.
This means that there are $$$4$$$ or $$$2$$$ or $$$0$$$ negative real roots.
Answer
$$$1$$$ positive real root.
$$$4$$$ or $$$2$$$ or $$$0$$$ negative real roots.