Find all the real zeros of the following polynomial. \[ f(x)=x^{5}+3 x^{3}-10 x \] Write your answers as exact values. Provide your answer below: \[ x=\square, \square, \square \]
Real Tutor Solution
Answer
Solution
Sign in to Unlock Answers for Free!
A Learning Platform Trusted by Millions of Real Students and Teachers.
Reviewed and approved by the UpStudy tutoring team
Beyond the Answer
To find the real zeros of the polynomial \( f(x) = x^5 + 3x^3 - 10x \), we can first factor out the common term: \[ f(x) = x(x^4 + 3x^2 - 10) \] Setting \( f(x) = 0 \), we have: \[ x(x^4 + 3x^2 - 10) = 0 \] This gives us one root: \( x = 0 \). Next, we need to solve the quartic equation \( x^4 + 3x^2 - 10 = 0 \). We can make a substitution by letting \( y = x^2 \), transforming the quartic into a quadratic: \[ y^2 + 3y - 10 = 0 \] Now we can apply the quadratic formula \( y = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \): \[ y = \frac{-3 \pm \sqrt{3^2 - 4 \cdot 1 \cdot (-10)}}{2 \cdot 1} = \frac{-3 \pm \sqrt{9 + 40}}{2} = \frac{-3 \pm \sqrt{49}}{2} = \frac{-3 \pm 7}{2} \] Calculating the two possible \( y \) values: 1. \( y = \frac{4}{2} = 2 \) 2. \( y = \frac{-10}{2} = -5 \) Since \( y = x^2 \) and \( x^2 = -5 \) does not yield real solutions, we focus on \( y = 2 \): \[ x^2 = 2 \implies x = \pm \sqrt{2} \] Thus, the real zeros of the polynomial are: \[ x = 0, \sqrt{2}, -\sqrt{2} \] So the final answer is: \[ x = 0, \sqrt{2}, -\sqrt{2} \]